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Costs of revenue, excluding depreciation and amortization

$ 1,890,180

$ 1,232,404

$ 3,048,364

$ 2,206,630

1,626,335

1,068,182

2,597,469

1,952,583

45,379

40,657

88,282

79,664

Equity in earnings of unconsolidated affiliates

70,823

67,852

135,604

127,900

Interest expense, net

14,791

12,639

27,388

24,797

(6,060)

(489)

(7,706)

(3,555)

146

1,524

576

(11,830)

138,766

42,039

206,751

37,071

(55,434)

(17,601)

(82,792)

(15,514)

Net income attributable to non-controlling interests

83,332

24,438

123,959

21,557

1,664

350

1,321

162

Basic earnings per share (in dollars per share)

^[1]

$ 81,668

$ 24,088

$ 122,638

$ 21,395

Earnings per share (Note 2):

$ 1.01

$ 0.30

$ 1.52

$ 0.27

Basic weighted average common shares outstanding

80,925

80,351

80,812

80,253

Diluted earnings per share (in dollars per share)

$ 0.99

$ 0.30

$ 1.49

$ 0.26

Diluted weighted average common shares outstanding

82,292

81,266

82,226

81,043

[1]	Calculated as total net income less amounts attributable to non-controlling interests.

Condensed Unaudited Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 83,332	$ 24,438	$ 123,959	$ 21,557
Other comprehensive income (loss):
Foreign currency translation gains, net of tax	595	247	1,774	5,871
Unrealized losses on equity investee activity, net of tax	(2,730)	(4,577)	(2,095)	(12,587)
Comprehensive income	81,197	20,108	123,638	14,841
Comprehensive income attributable to non-controlling interests	1,664	350	1,321	162
Comprehensive income attributable to MasTec, Inc.	$ 79,533	$ 19,758	$ 122,317	$ 14,679

Condensed Unaudited Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 18,230	$ 38,767
Accounts receivable, net	1,569,392	1,156,031
Inventories, net	95,541	111,031
Prepaid expenses	80,270	41,548
Other current assets	27,274	55,109
Total current assets	1,790,707	1,402,486
Property and equipment, net	648,456	549,084
Goodwill, net	1,040,302	995,874
Other intangible assets, net	185,932	179,711
Other long-term assets	158,088	55,977
Total assets	3,823,485	3,183,132
Current liabilities:
Current portion of long-term debt	75,401	64,600
Accounts payable	429,623	363,668
Accrued salaries and wages	112,180	67,126
Other accrued expenses	134,801	112,291
Billings in excess of costs and earnings	102,965	161,459
Other current liabilities	73,761	70,846
Total current liabilities	928,731	839,990
Long-term debt	1,313,860	961,379
Deferred income taxes	252,834	178,355
Other long-term liabilities	94,898	99,774
Total liabilities	2,590,323	2,079,498
Commitments and contingencies (Note 14)
Equity
Preferred stock, $1.00 par value: authorized shares - 5,000,000; issued and outstanding shares – none	0	0
Common stock, $0.10 par value: authorized shares - 145,000,000; issued shares - 90,825,531 and 90,634,771 (including 1,802,346 and 1,927,286 of unvested restricted shares) as of June 30, 2017 and December 31, 2016, respectively	9,083	9,063
Capital surplus	796,065	788,914
Retained earnings	632,579	509,941
Accumulated other comprehensive loss	(66,135)	(65,814)
Treasury stock, at cost: 8,094,004 shares as of both June 30, 2017 and December 31, 2016	(145,573)	(145,573)
Total MasTec, Inc. shareholders’ equity	1,226,019	1,096,531
Non-controlling interests	7,143	7,103
Total equity	1,233,162	1,103,634
Total liabilities and equity	$ 3,823,485	$ 3,183,132

Condensed Unaudited Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized	145,000,000	145,000,000
Common stock, shares issued	90,825,531	90,634,771
Treasury stock, shares	8,094,004	8,094,004
Restricted Shares [Member] \| Common Stock [Member]
Unvested restricted shares (in shares)	1,802,346	1,927,286

Condensed Unaudited Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income	$ 123,959	$ 21,557
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Depreciation and amortization	88,282	79,664
Non-cash interest expense, net	1,615	1,473
Non-cash stock-based compensation expense	7,166	7,405
Provision for deferred income taxes	76,584	1,155
Equity in earnings of unconsolidated affiliates	(7,706)	(3,555)
(Gains) losses on sales of assets, net, including fixed assets held-for-sale	(1,873)	1,177
Other non-cash items, net	13,190	2,098
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	(388,818)	(179,372)
Inventories	28,295	(26,454)
Other assets, current and long-term portion	(81,286)	32,433
Accounts payable and accrued expenses	113,975	123,958
Billings in excess of costs and earnings	(58,594)	(18,856)
Book overdrafts	(9,760)	10,075
Other liabilities, current and long-term portion	6,978	(24,270)
Net cash (used in) provided by operating activities	(87,993)	28,488
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	(37,444)	(4,102)
Capital expenditures	(56,853)	(63,893)
Proceeds from sale of property and equipment	7,369	10,163
Payments for other investments	(74,482)	(2,735)
Proceeds from other investments	12,118	695
Net cash used in investing activities	(149,292)	(59,872)
Cash flows from financing activities:
Proceeds from credit facilities	1,153,230	684,287
Repayments of credit facilities	(869,100)	(604,640)
Repayments of other borrowings	(10,291)	(5,993)
Payments of capital lease obligations	(30,858)	(27,506)
Payments of acquisition-related contingent consideration	(18,843)	(14,572)
Distributions to non-controlling interests	(1,280)	0
Proceeds from stock-based awards, net	5	3,338
Other financing activities, net	(6,240)	1,132
Net cash provided by financing activities	216,623	36,046
Effect of currency translation on cash	125	(888)
Net (decrease) increase in cash and cash equivalents	(20,537)	3,774
Cash and cash equivalents - beginning of period	38,767	4,984
Cash and cash equivalents - end of period	18,230	8,758
Supplemental cash flow information:
Interest paid	25,743	22,647
Income taxes paid, net of refunds	76,633	7,131
Supplemental disclosure of non-cash information:
Equipment acquired under capital lease and financing arrangements	109,914	3,481
Accrued capital expenditures	$ 1,499	$ 6,090

Business, Basis of Presentation and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Business, Basis of Presentation and Significant Accounting Policies	Note 1 – Business, Basis of Presentation and Significant Accounting Policies Nature of the Business MasTec, Inc. (collectively with its subsidiaries, “MasTec” or the “Company”) is a leading infrastructure construction company operating mainly throughout North America across a range of industries. The Company’s primary activities include the engineering, building, installation, maintenance and upgrade of communications, energy and utility infrastructure, such as: wireless, wireline/fiber, install-to-the-home and customer fulfillment activities; petroleum and natural gas pipeline infrastructure; electrical utility transmission and distribution; power generation; and industrial infrastructure. MasTec’s customers are primarily in these industries. MasTec reports its results under five reportable segments: (1) Communications; (2) Oil and Gas; (3) Electrical Transmission; (4) Power Generation and Industrial; and (5) Other. Basis of Presentation The accompanying condensed unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X. Pursuant to these rules and regulations, certain information and footnote disclosures normally included in the annual audited consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The accompanying condensed consolidated balance sheet as of December 31, 2016 is derived from the Company’s audited financial statements as of that date. Because certain information and footnote disclosures have been condensed or omitted, these condensed unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto as of and for the year ended December 31, 2016 contained in the Company’s 2016 Annual Report on Form 10-K (the “2016 Form 10-K”). In management’s opinion, all normal and recurring adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented have been included. Certain prior year amounts have been reclassified to conform to the current period presentation. Interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. The Company believes that the disclosures made in these condensed unaudited consolidated financial statements are adequate to make the information not misleading. Principles of Consolidation The accompanying condensed unaudited consolidated financial statements include MasTec, Inc. and its subsidiaries and include the accounts of all majority owned subsidiaries over which the Company exercises control and, when applicable, entities in which the Company has a controlling financial interest. All significant intercompany balances and transactions have been eliminated in consolidation. Other parties’ interests in entities that MasTec consolidates are reported as non-controlling interests within equity. Net income or loss attributable to non-controlling interests is reported as a separate line item below net income or loss. The Company’s investments in entities for which the Company does not have a controlling interest, but for which it has the ability to exert significant influence, are accounted for using the equity method of accounting. Equity method investments are recorded as other long-term assets, or, for investments in a net liability position, within other long-term liabilities. Income or loss from these investments is recorded as a separate line item in the statements of operations. Intercompany profits or losses associated with the Company’s equity method investments are eliminated until realized by the investee in transactions with third parties. For equity investees in which the Company has an undivided interest in the assets, liabilities and profits or losses of an unincorporated entity, but the Company does not exercise control over the entity, the Company consolidates its proportional interest in the accounts of the entity. The cost method is used for investments in entities for which the Company does not have the ability to exert significant influence. Management determines whether each business entity in which it has equity interests, debt, or other investments constitutes a variable interest entity (“VIE”) based on the nature and characteristics of such arrangements. If an investment arrangement is determined to be a VIE, then management determines if the Company is the VIE’s primary beneficiary by evaluating several factors, including the Company’s: (i) risks and responsibilities; (ii) ownership interests; (iii) decision making powers; and (iv) financial interests, among other factors. If management determines the Company is the primary beneficiary of a VIE, then it would be consolidated, and other parties’ interests in the VIE would be accounted for as non-controlling interests. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the primary activities of the VIE and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, which, in either case, could be significant to the VIE. As of June 30, 2017, the Company determined that certain of its investment arrangements were VIEs; however, because it does not have the power to direct the primary activities that most significantly impact the economic performance of these VIEs, the Company is not the primary beneficiary, and accordingly, has not consolidated these VIEs. Translation of Foreign Currencies The assets and liabilities of foreign subsidiaries with a functional currency other than the U.S. dollar are translated into U.S. dollars at period-end exchange rates, with resulting translation gains or losses accumulated within other comprehensive income or loss. Revenue and expenses are translated into U.S. dollars at average rates of exchange during the applicable period. Substantially all of the Company’s foreign operations use their local currency as their functional currency. Currency gains or losses resulting from transactions executed in currencies other than the functional currency are included in other income or expense, net. In these condensed unaudited consolidated financial statements, “$” means U.S. dollars unless otherwise noted. Management Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires the use of estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Key estimates include: the recognition of revenue and project profit or loss (which the Company defines as project revenue, less project costs of revenue, including project-related depreciation), in particular, on construction contracts accounted for under the percentage-of-completion method, for which the recorded amounts require estimates of costs to complete and the amount of probable contract price adjustments; allowances for doubtful accounts; estimated fair values of goodwill and intangible assets; acquisition-related contingent consideration and investments in equity investees; asset lives used in computing depreciation and amortization; accrued self-insured claims; share-based compensation; other accruals and allowances; accounting for income taxes; and the estimated impact of litigation and other contingencies. While management believes that such estimates are reasonable when considered in conjunction with the Company’s consolidated financial position and results of operations taken as a whole, actual results could differ materially from those estimates. Significant Accounting Policies Revenue Recognition Revenue is derived from construction projects performed under master and other service agreements as well as from contracts for specific projects or jobs requiring the construction and installation of an entire infrastructure system or specified units within an entire infrastructure system. The Company frequently provides services under unit price or fixed price master service or other service agreements. Revenue and related costs for master and other service agreements billed on a time and materials basis are recognized as the services are rendered. Revenue derived from projects performed under master service and other service agreements totaled 31% and 45% of consolidated revenue for the three month periods ended June 30, 2017 and 2016, respectively, and totaled 37% and 47% for the six month periods ended June 30, 2017 and 2016, respectively. The Company also performs services under master and other service agreements on a fixed fee basis, under which MasTec furnishes specified units of service for a fixed price per unit of service and revenue is recognized as the services are rendered. Revenue from fixed price contracts provides for a fixed amount of revenue for the entire project, subject to certain additions for changed scope or specifications. Revenue from these contracts, as well as for certain projects pursuant to master and other service agreements, is recognized using the percentage-of-completion method, under which the percentage of revenue to be recognized for a given project is measured by the percentage of costs incurred to date on the contract to the total estimated costs for the contract. Such contracts provide that the customer accept completion of progress to date and compensate the Company for services rendered, which may be measured in terms of costs incurred, units installed, hours expended or some other measure of progress. Contract costs include all direct materials, labor and subcontracted costs and those indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and the operational costs of capital equipment. Much of the materials associated with the Company’s work are customer-furnished and are therefore not included in contract revenue and costs. The estimation process for revenue recognized under the percentage-of-completion method is based on the professional knowledge and experience of the Company’s project managers, engineers and financial professionals. Management reviews estimates of contract revenue and costs on an ongoing basis. Changes in job performance, job conditions and management’s assessment of expected contract settlements are factors that influence estimates of total contract value and total costs to complete those contracts and, therefore, the Company’s profit recognition. Changes in these factors may result in revisions to costs and income and their effects are recognized in the period in which the revisions are determined, which could materially affect the Company’s results of operations in the period in which such changes are recognized. For both the six month periods ended June 30, 2017 and 2016, project profit was affected by less than 5% as a result of changes in contract estimates included in projects that were in process as of December 31, 2016 and 2015. Provisions for losses on uncompleted contracts are made in the period in which such losses are determined to be probable and the amount can be reasonably estimated. The majority of fixed price contracts are completed within one year. The Company may incur costs subject to change orders, whether approved or unapproved by the customer, and/or claims related to certain contracts. Management determines the probability that such costs will be recovered based upon engineering studies and legal opinions, past practices with the customer, specific discussions, correspondence or preliminary negotiations with the customer. The Company treats such costs as a cost of contract performance in the period incurred if it is not probable that the costs will be recovered, and defers costs or recognizes revenue up to the amount of the related cost if it is probable that the contract price will be adjusted and can be reliably estimated. As of June 30, 2017 and December 31, 2016, the Company had approximately $19 million and $17 million, respectively, of change orders and/or claims that had been included as contract price adjustments on certain contracts that were in the process of being resolved in the normal course of business, including through negotiation, arbitration and other proceedings. These contract price adjustments, which are included within costs and earnings in excess of billings or billed accounts receivable, as appropriate, represent management’s best estimate of contract revenue that has been earned and that management believes is probable of collection. As of both June 30, 2017 and December 31, 2016, these change orders were primarily related to contracts in the Oil and Gas segment. The Company actively engages in substantive meetings with its customers to complete the final approval process, and generally expects these processes to be completed within one year. The amounts ultimately realized upon final acceptance by its customers could be higher or lower than such estimated amounts. Billings In Excess of Costs and Earnings (“BIEC”) on uncompleted contracts is classified within current liabilities. Costs and Earnings In Excess of Billings (“CIEB”), which is also referred to as work in process, is classified within current assets. Work in process on contracts is based on work performed but not yet billed to customers as per individual contract terms. Recently Issued Accounting Pronouncements There have been no changes in the expected dates of adoption or estimated effects on the Company’s consolidated financial statements of recently issued accounting pronouncements from those disclosed in the Company’s 2016 Form 10-K. See below for additional discussion of recently issued accounting pronouncements. Accounting Pronouncements Not Yet Adopted In May 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”). ASU 2017-09 clarifies when a change to the terms or conditions of a share-based payment award must be accounted for as modifications. Limited and administrative modifications that do not change the value, vesting conditions, or classification of the award are exempt from following the modification guidance in Topic 718. ASU 2017-09 is effective on a prospective basis for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The Company does not expect the adoption of this ASU to have a material effect on its consolidated financial statements. In February 2017, the FASB issued ASU 2017-05, Other Income- Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets (“ASU 2017-05”). ASU 2017-05 clarifies certain guidance under Subtopic 610-20 that was issued as part of the new revenue standard, including the recognition of gains and losses on the sale or transfer of nonfinancial assets to noncustomers, and clarifies accounting for contributions of nonfinancial assets to joint ventures, among other requirements. ASU 2017-05 is effective on a retrospective basis for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the potential effect of this ASU on its consolidated financial statements. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”). The core principle of this ASU is that a company will recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. In doing so, companies will need to use judgment and make estimates when evaluating contract terms and other relevant facts and circumstances. Additionally, ASU 2014-09 requires enhanced disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which delayed the effective date of ASU 2014-09 by one year. ASU 2014-09, as amended, is effective using either the full retrospective or modified retrospective transition approach for fiscal years, and for interim periods within those years, beginning after December 15, 2017. In 2016, the FASB issued several accounting standards updates to clarify certain topics within ASU 2014-09. The Company will adopt ASU 2014-09, and its related clarifying ASUs, as of January 1, 2018. The Company has substantially completed its assessment of the potential effects of these ASUs on its consolidated financial statements, business processes, systems and controls. The Company’s assessment included a detailed review of representative contracts at each of the Company’s business units and a comparison of its historical accounting policies and practices to the new standard. Based on the Company’s review of various types of revenue arrangements, the Company expects to recognize revenue and earnings over time utilizing the cost-to-cost measure of progress for its fixed price contracts and certain master service and other service agreements, consistent with current practice. For these contracts, the cost-to-cost measure of progress best depicts the transfer of control of goods or services to the customer under the new standard. Under the new standard and consistent with the Company’s current practice, the cost of uninstalled materials will generally be excluded from the measure of progress, unless specifically produced or fabricated for a project, because such cost does not appropriately depict the Company’s performance in transferring control of goods or services to the customer. The Company has substantially completed its analysis of the information necessary to enable the preparation of the financial statements and related disclosures under the new standard. As part of this analysis, the Company evaluated its information technology capabilities and systems, and does not expect to incur significant information technology costs to modify systems currently in place. The Company will implement targeted changes to its internal reporting processes to facilitate gathering the data needed for the new disclosure requirements. The Company will also implement updates to its control processes and procedures, as necessary, based on changes resulting from the new standard. The Company does not expect any such updates to materially affect the Company’s internal controls over financial reporting. The Company anticipates adopting the standard using the modified retrospective transition approach. Under this approach, the new standard would apply to all new contracts initiated on or after January 1, 2018. For existing contracts that have remaining obligations as of January 1, 2018, any difference between the recognition criteria in these ASUs and the Company’s current revenue recognition practices would be recognized using a cumulative effect adjustment to the opening balance of retained earnings. Any potential effect of adoption of these ASUs has not yet been quantified; however, based on the review of contracts across all of the Company’s business units to date, the adoption of these ASUs is not expected to have a material effect on the timing or amount of revenue recognized as compared to current practices. The Company expects to begin training its business units for the implementation of the new standard, and to continue developing the disclosures required by the new standard during the third quarter of 2017. Accounting Pronouncements Adopted as of January 1, 2017 The Company adopted ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”) effective January 1, 2017. Under ASU 2016-09, excess tax benefits (“windfalls”) or tax deficiencies (“shortfalls”) are recognized in the income statement, rather than as additional paid-in-capital as under the previous guidance, and are presented as operating cash flows, rather than as a financing activity. This ASU also increased the amount of tax that can be withheld by an employer for employee tax withholdings without resulting in liability classification of an award. Payments to taxing authorities for such employee withholdings are presented as financing activities. ASU 2016-09 also allows companies to account for forfeitures of share-based payments as they occur or to estimate such amounts. The provisions of ASU 2016-09 that were applicable to the Company were adopted on a prospective basis; the retrospective requirement to classify payments to taxing authorities for employee withholdings as a financing activity was consistent with the Company’s existing methodology, therefore did not result in a change. The adoption of ASU 2016-09 is expected to result in volatility in income tax expense given that windfalls or shortfalls are recognized in income tax expense in the periods in which they occur. The other components of this ASU did not have a material effect on the consolidated financial statements. See Note 2 - Earnings Per Share, Note 9 - Stock-Based Compensation and Other Employee Benefit Plans and Note 12 - Income Taxes for additional information.

Earnings Per Share

6 Months Ended

Jun. 30, 2017

Earnings Per Share [Abstract]

Earnings Per Share

Note 2 – Earnings Per Share

Basic earnings or loss per share is computed by dividing net income or loss attributable to MasTec by the weighted average number of common shares outstanding for the period, which excludes non-participating unvested restricted share awards. Diluted earnings per share is computed by dividing net income attributable to MasTec by the weighted average number of fully diluted shares, as calculated under the treasury stock method, which includes the potential effect of dilutive common stock equivalents, such as issued but unvested restricted shares and/or outstanding but unexercised stock options. The Company has no remaining outstanding stock options; all options under the Company’s stock option grants were exercised in 2016. If the Company reports a loss, rather than income, the computation of diluted loss per share excludes the effect of dilutive common stock equivalents, as their effect would be anti-dilutive.

As discussed in Note 1 - Business, Basis of Presentation and Significant Accounting Policies, the Company adopted ASU 2016-09 effective January 1, 2017 on a prospective basis. ASU 2016-09 changed the recognition of excess tax benefits or tax deficiencies upon the vesting of share-based payment awards from additional paid-in capital, within equity, to income tax benefit or expense, within the statement of operations. As a result, excess tax benefits or deficiencies under ASU 2016-09 are excluded from assumed proceeds under the treasury stock method. Previously, excess tax benefits or tax deficiencies were included within assumed proceeds. For both the three and six month periods ended June 30, 2017, this resulted in the inclusion of approximately 0.3 million incremental shares in the Company’s total weighted average diluted shares outstanding.

The following table provides details underlying the Company’s earnings per share calculations for the periods indicated (in thousands):



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2017		2016		2017		2016
Net income attributable to MasTec:
Net income - basic and diluted ^(a)	$	81,668	$	24,088	$	122,638	$	21,395
Weighted average shares outstanding:
Weighted average shares outstanding - basic	80,925		80,351		80,812		80,253
Dilutive common stock equivalents	1,367		915		1,414		790
Weighted average shares outstanding - diluted	82,292		81,266		82,226		81,043

Additional information:
Weighted average anti-dilutive common stock equivalents ^(b)	13		—		6		3


(a)	Calculated as total net income less amounts attributable to non-controlling interests.


(b)	Represents anti-dilutive common stock equivalents as calculated under the treasury stock method.

Goodwill and Other Intangible Assets

6 Months Ended

Jun. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

Note 3 - Goodwill and Other Intangible Assets

The following table provides details of goodwill by reportable segment as of June 30, 2017 (in millions):



	Communications		Oil and Gas			Electrical Transmission		Power Generation and Industrial		Total Goodwill
Goodwill, gross	$	463.1	$	382.2		$	149.9	$	117.6	$	1,112.8
Accumulated impairment losses	—		(72.5		)	—		—		(72.5		)
Goodwill, net	$	463.1	$	309.7		$	149.9	$	117.6	$	1,040.3

For the six month period ended June 30, 2017, additions to goodwill from new business combinations totaled $42.4 million. Currency translation effects related to goodwill and accumulated impairment losses totaled approximately $4.6 million of gains and $2.6 million of losses, respectively, for the six month period ended June 30, 2017. For the six month period ended June 30, 2016, additions to goodwill from accruals of acquisition-related contingent consideration totaled $5.8 million, and currency translation effects related to goodwill and accumulated impairment losses totaled $8.0 million of gains and $4.2 million of losses, respectively.

The following table provides a reconciliation of changes in other intangible assets for the period indicated (in millions):



	Other Intangible Assets
	Non-Amortizing				Amortizing
	Trade Names		Pre-Qualifications		Customer Relationships and Backlog			Other ^(a)			Total
Other intangible assets, gross, as of December 31, 2016	$	34.5	$	74.6	$	195.1		$	19.1		$	323.3
Accumulated amortization					(131.9		)	(11.7		)	(143.6		)
Other intangible assets, net, as of December 31, 2016	$	34.5	$	74.6	$	63.2		$	7.4		$	179.7
Additions from new business combinations	—		—		12.8			0.6			13.4
Amortization expense					(8.4		)	(0.6		)	(9.0		)
Currency translation adjustments	—		1.6		0.3			(0.1		)	1.8
Other intangible assets, net, as of June 30, 2017	$	34.5	$	76.2	$	67.9		$	7.3		$	185.9


(a)	Consists principally of trade names and non-compete agreements.

Amortization expense associated with intangible assets for the three month periods ended June 30, 2017 and 2016 totaled $4.9 million and $5.3 million, respectively, and for the six month periods ended June 30, 2017 and 2016, totaled $9.0 million and $10.5 million, respectively.

2017 Acquisitions. In April 2017, MasTec acquired a leading wireline/fiber deployment construction contractor with operations in several western states, predominantly servicing cable system operators, for an aggregate purchase price composed of approximately $38.2 million in cash and a five year earn-out, valued at $25.0 million, which is included in the Company’s Communications segment. As of June 30, 2017, determination of the estimated fair values of the net assets acquired and the estimated earn-out liability were preliminary, and further adjustments to these purchase accounting estimates may occur.

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Fair Value of Financial Instruments	6 Months Ended
Fair Value of Financial Instruments	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Note 4 – Fair Value of Financial Instruments The Company’s financial instruments include cash and cash equivalents, accounts and notes receivable, cash collateral deposited with insurance carriers, life insurance assets, cost and equity method investments, deferred compensation plan assets and liabilities, accounts payable and other current liabilities, acquisition-related contingent consideration, certain intangible assets and liabilities, including off-market contracts, and debt obligations. Fair value is the price that would be received to sell an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value guidance establishes a valuation hierarchy, which requires maximizing the use of observable inputs when measuring fair value. The three levels of inputs that may be used are: (i) Level 1 - quoted market prices in active markets for identical assets or liabilities; (ii) Level 2 - observable market-based inputs or other observable inputs; and (iii) Level 3 - significant unobservable inputs that cannot be corroborated by observable market data, which are generally determined using valuation models incorporating management estimates of market participant assumptions. In instances in which the inputs used to measure fair value fall into different levels of the fair value hierarchy, the fair value measurement classification is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Management’s assessment of the significance of a particular item to the fair value measurement in its entirety requires judgment, including the consideration of inputs specific to the asset or liability. Fair values of financial instruments are estimated using public market prices, quotes from financial institutions and other available information. Due to their short-term maturity, the carrying amounts of cash and cash equivalents, accounts receivable, accounts payable and other current liabilities approximate their fair values. Management believes the carrying values of notes and other receivables, cash collateral deposited with insurance carriers, deferred compensation plan assets and liabilities and outstanding balances on its credit facilities approximate their fair values. Assets and Liabilities Measured at Fair Value on a Recurring Basis As of June 30, 2017 and December 31, 2016, financial instruments required to be measured at fair value on a recurring basis consisted primarily of acquisition-related contingent consideration, which represents the estimated fair value of future earn-outs payable for acquisitions of businesses (“ASC 805 contingent consideration”). ASC 805 contingent consideration is based on management estimates and entity-specific assumptions and is evaluated on an ongoing basis. As of June 30, 2017 and December 31, 2016, the fair value of the Company’s ASC 805 contingent consideration totaled $43.3 million and $45.8 million, respectively, of which $19.1 million and $21.8 million, respectively, was included within other current liabilities. The fair value of the Company’s ASC 805 contingent consideration is estimated using an income approach and incorporates significant inputs not observable in the market. These assumptions include the discount rate and probability-weighted earnings before interest, taxes, depreciation and amortization (“EBITDA”) projections. Significant changes in any of these assumptions could result in a significantly higher or lower potential earn-out liability. As of June 30, 2017, the range of potential undiscounted earn-out liabilities was estimated to be between $9 million and $69 million; however, there is no maximum payment amount. ASC 805 contingent consideration activity consists primarily of additions from new business combinations, payments of earn-out liabilities, changes in the expected fair value of future earn-out obligations, and, for earn-out liabilities denominated in foreign currencies, translation gains or losses. Fair value adjustments are recorded within other income or expense, and foreign currency translation activity is recorded within other comprehensive income or loss, as appropriate. For both the three and six month periods ended June 30, 2017, additions from new business combinations totaled $25.0 million. Payments in connection with ASC 805 contingent consideration totaled $18.8 million for both the three and six month periods ended June 30, 2017, and totaled $10.6 million for both the three and six month periods ended June 30, 2016. Foreign currency translation losses were de minimis for the three month period ended June 30, 2016, and totaled $0.6 million for the six month period ended June 30, 2016. During the second quarter of 2017, the Company recognized a decrease in the expected fair value of future earn-out obligations of $8.6 million for a business in the Company’s Communications segment, and during the first quarter of 2016, the Company recognized a net reduction in the expected fair value of future earn-out obligations of $2.3 million for certain of the Company’s western Canadian oil and gas businesses due to finalization of completed earn-out arrangements and adjustments to expected future period earn-out obligations. Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis Assets and liabilities recognized or disclosed at fair value on a non-recurring basis, for which remeasurement occurs in the event of an impairment or other measurement event, if applicable, include items such as cost and equity method investments, life insurance assets, long-lived assets, goodwill, other intangible assets and liabilities and debt. As of both June 30, 2017 and December 31, 2016, the gross carrying amount of the Company’s 4.875% senior notes due 2023 (the “4.875% Senior Notes”) totaled $400 million. As of June 30, 2017 and December 31, 2016, the estimated fair value of the Company’s 4.875% Senior Notes, based on quoted market prices in active markets, a Level 1 input, totaled $398.0 million and $388.0 million, respectively. Cost and Equity Investees. The Company’s cost and equity investees as of June 30, 2017 are primarily composed of: (i) the Company’s equity interests in Trans-Pecos Pipeline, LLC (“TPP”) and Comanche Trail Pipeline, LLC (“CTP,” and together with TPP, the “Waha JVs”); (ii) the Company’s interests in a pre-acquisition equity method investment of Pacer Construction Holdings Corporation and its affiliated operating companies (collectively, “Pacer”); (iii) a $15 million cost investment in Cross Country Infrastructure Services, Inc. (“CCI,” previously, Cross Country Pipeline Supply, Inc.); (iv) the Company’s interests in certain proportionately consolidated non-controlled contractual joint ventures; and (v) certain other cost and equity method investments. See Note 15 - Related Party Transactions. The fair values of the Company’s cost and equity method investments are not readily observable. The Company is not aware of events or changes in circumstances that would have a significant adverse effect on the carrying values of its cost and/or equity investments as of June 30, 2017 or December 31, 2016. Cumulative undistributed earnings from equity method investees totaled $3.3 million as of June 30, 2017. The Waha JVs. The Waha JVs own and operate two pipelines and a header system that transport natural gas to the Mexican border for export. These pipelines commenced operations in the first half of 2017. For the three and six month periods ended June 30, 2017, the Company made equity and other contributions to these joint ventures of approximately $19.9 million and $73.3 million, respectively. As collateral for its equity commitments in the Waha JVs, the Company has issued letters of credit (the “Equity LC Amount”), of which $19 million and $91 million, respectively, were outstanding as of June 30, 2017 and December 31, 2016. Equity in earnings related to the Company’s proportionate share of income from the Waha JVs, which is included within the Company’s Other segment, totaled approximately $6.1 million and $7.7 million for the three and six month periods ended June 30, 2017, respectively, and totaled $0.5 million for the three month period ended June 30, 2016. Equity in earnings from the Waha JVs for the six month period ended June 30, 2016 was de minimis. The Waha JVs are party to certain interest rate swaps. The Company reflects its proportionate share of any unrealized fair market value gains or losses from fluctuations in interest rates associated with these swaps in its financial statements. For the three and six month periods ended June 30, 2017, the Company’s proportionate share of unrecognized unrealized activity on these interest rate swaps was a loss of approximately $4.4 million and $3.4 million, respectively, or $2.7 million and $2.1 million, net of tax, respectively, which amounts are included within other comprehensive income or loss, as appropriate. For the three and six month periods ended June 30, 2016, the Company’s proportionate share of unrecognized unrealized activity on these interest rate swaps was a loss of approximately $7.5 million and $20.5 million, respectively, or $4.6 million and $12.6 million, net of tax, respectively. Certain subsidiaries of MasTec have provided pipeline construction services to the Waha JVs. For the three and six month periods ended June 30, 2017, revenue recognized in connection with work performed for the Waha JVs, including intercompany eliminations, totaled $100.2 million and $251.6 million, respectively, and for the three and six month periods ended June 30, 2016, totaled $51.6 million and $61.9 million, respectively. As of June 30, 2017 and December 31, 2016, related receivables, including retainage, net of BIEC, totaled $54.1 million and $71.2 million, respectively. As of June 30, 2017 and December 31, 2016, the Company’s net investment in the Waha JVs represented an asset totaling approximately $107 million and $6 million, respectively. The Company’s net investment in the Waha JVs differs from its proportionate share of the net assets of the Waha JVs due to capitalized investment costs as well as the effect of intercompany eliminations. Other investments. In connection with the 2014 acquisition of Pacer, the Company acquired equity interests in two joint ventures. There are no remaining amounts expected to be advanced in connection with these investments, and as of March 2016, all related project work had been completed. In the first quarter of 2016, revenue recognized by Pacer on behalf of these entities totaled $0.6 million. One of these entities was liquidated in 2016, and the second, which is in the final stages of liquidation, is being managed by a receiver to assist with the orderly wind-down of its operations. In the first quarter of 2016, $3.6 million of income was recognized related to changes in expected recoveries from these investments. The Company received $12.1 million of proceeds from the receiver in the first quarter of 2017. The remaining investment, for which the Company now has minimal involvement, is reviewed regularly by corporate management for potential changes in expected recovery estimates, and, during the second quarter of 2017, the Company recorded $5.8 million of expense related to changes in expected recovery amounts from this investment. The aggregate net carrying value of this investment, which represents expected recoveries under the receivership arrangement, totaled $14.3 million and $31.4 million as of June 30, 2017 and December 31, 2016, respectively, which amounts are included within other current assets.

Accounts Receivable, Net of Allowance

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Accounts Receivable, Net of Allowance

6 Months Ended

Jun. 30, 2017

Receivables [Abstract]

Note 5 - Accounts Receivable, Net of Allowance

The following table provides details of accounts receivable, net of allowance, as of the dates indicated (in millions):



	June 30, 2017			December 31, 2016
Contract billings	$	784.5		$	564.2
Retainage	228.6			268.6
Costs and earnings in excess of billings	565.1			331.6
Accounts receivable, gross	$	1,578.2		$	1,164.4
Less allowance for doubtful accounts	(8.8		)	(8.4		)
Accounts receivable, net	$	1,569.4		$	1,156.0

Retainage, which has been billed, but is not due until completion of performance and acceptance by customers, is expected to be collected within one year. Receivables expected to be collected beyond one year are recorded within other long-term assets. Provisions for doubtful accounts for the three month periods ended June 30, 2017 and 2016 totaled $0.2 million and $1.3 million, respectively, and for the six month periods ended June 30, 2017 and 2016, totaled $0.7 million and $1.7 million, respectively.

The Company is party to non-recourse financing arrangements in the ordinary course of business, under which certain receivables are purchased by the customer’s bank in return for a nominal fee. These arrangements, under which amounts can vary based on levels of activity and changes in customer payment terms, improve the collection cycle time of the related receivables. The discount charge, which is included within interest expense, totaled approximately $1.7 million and $0.5 million, respectively, for the three month periods ended June 30, 2017 and 2016, and totaled approximately $2.6 million and $0.9 million, respectively, for the six month periods ended June 30, 2017 and 2016.

Property, Plant and Equipment [Abstract]

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Property and Equipment, Net

6 Months Ended

Jun. 30, 2017

Property and Equipment, Net

Note 6 - Property and Equipment, Net

The following table provides details of property and equipment, net, including property and equipment held under capital leases as of the dates indicated (in millions):



	June 30, 2017			December 31, 2016
Land	$	4.6		$	4.6
Buildings and leasehold improvements	26.2			24.2
Machinery and equipment	1,155.6			997.8
Office furniture and equipment	148.9			146.1
Construction in progress	12.3			9.5
Total property and equipment	$	1,347.6		$	1,182.2
Less accumulated depreciation and amortization	(699.1		)	(633.1		)
Property and equipment, net	$	648.5		$	549.1

The gross amount of capitalized internal-use software, which is included within office furniture and equipment, totaled $108.9 million and $107.8 million as of June 30, 2017 and December 31, 2016, respectively. Capitalized internal-use software, net of accumulated amortization, totaled $26.8 million and $30.9 million as of June 30, 2017 and December 31, 2016, respectively. Depreciation and amortization expense associated with property and equipment for the three month periods ended June 30, 2017 and 2016 totaled $40.5 million and $35.4 million, respectively, and totaled $79.2 million and $69.1 million for the six month periods ended June 30, 2017 and 2016, respectively.

Debt

6 Months Ended

Jun. 30, 2017

Debt Disclosure [Abstract]

Debt

Note 7 - Debt

The following table provides details of the carrying values of debt as of the dates indicated (in millions):



Description	Maturity Date	June 30, 2017			December 31, 2016
Senior secured credit facility:	February 22, 2022
Revolving loans		$	564.6		$	279.9
Term loan		250.0			237.5
4.875% Senior Notes	March 15, 2023	400.0			400.0
Capital lease obligations, weighted average interest rate of 3.3%	In installments through June 30, 2022	177.9			98.6
Notes payable and other debt obligations	Varies	11.2			19.8
Total long-term debt obligations		$	1,403.7		$	1,035.8
Less unamortized deferred financing costs		(14.4		)	(9.8		)
Total debt, net of deferred financing costs		$	1,389.3		$	1,026.0
Current portion of long-term debt		75.4			64.6
Long-term debt		$	1,313.9		$	961.4

Senior Secured Credit Facility

The Company has a senior secured credit facility, (the “Credit Facility”), which was amended and restated on February 22, 2017. The Company refers to its amended and restated credit facility as the “2017 Credit Facility,” and to its previous credit facility as the “2016 Credit Facility.” The 2017 Credit Facility increased the Company’s aggregate borrowing commitments from approximately $1.2 billion to $1.5 billion, which amount is composed of $1.1 billion of revolving commitments and a term loan in the aggregate principal amount of $400 million. The amended and restated credit facility also extended the Credit Facility’s maturity date to February 22, 2022. As of June 30, 2017, term loans in the aggregate principal amount of $250 million were drawn under the 2017 Credit Facility, and additional term loans of $150 million were drawn in July 2017. The term loan is subject to amortization in quarterly principal installments that commence in December 2017, which as of June 30, 2017, amounted to $3.1 million. This amount is subject to adjustment for the additional term loans and, if applicable, certain prepayments. As of December 31, 2016, term loans in the aggregate principal amount of $238 million were outstanding.

The 2017 Credit Facility also increased the amount the Company can borrow either in Canadian dollars and/or Mexican pesos up to an aggregate equivalent amount of $300 million. The maximum amount available for letters of credit under the 2017 Credit Facility is $650 million, of which up to $200 million can be denominated in either Canadian dollars and/or Mexican pesos. The Credit Facility also provides for swing line loans of up to $75 million, and, subject to certain conditions, the Company has the option to increase revolving commitments and/or establish additional term loan tranches up to an aggregate amount of $250 million. Subject to the terms and conditions described in the Credit Facility, these additional term loan tranches may rank equal or junior in respect of right of payment and/or collateral to the Credit Facility, and may have terms and pricing that differ from the 2017 Credit Facility. Borrowings under the Credit Facility are used for working capital requirements, capital expenditures and other corporate purposes, including investments in equity or other investees, potential acquisitions or other strategic arrangements, and the repurchase or prepayment of indebtedness.

Outstanding revolving loans and the term loan under the Credit Facility bear interest, at the Company’s option, at a rate equal to either (a) a Eurocurrency Rate, as defined in the 2017 Credit Facility, plus a margin of 1.25% to 2.00% (under the 2016 Credit Facility, the margin was from 1.00% to 2.00%), or (b) a Base Rate, as defined in the 2017 Credit Facility, plus a margin of 0.25% to 1.00% (under the 2016 Credit Facility, the margin was from 0.00% to 1.00%). The Base Rate equals the highest of (i) the Federal Funds Rate, as defined in the Credit Facility, plus 0.50%, (ii) Bank of America’s prime rate, and (iii) the Eurocurrency Rate plus 1.00%. Financial standby letters of credit and commercial letters of credit issued under the 2017 Credit Facility are subject to a letter of credit fee of 1.25% to 2.00% (under the 2016 Credit Facility, the letter of credit fee was from 1.00% to 2.00%), and performance standby letters of credit are subject to a letter of credit fee of 0.50% to 1.00% under the Credit Facility. The Company must also pay a commitment fee to the lenders of 0.20% to 0.40% on any unused availability under the Credit Facility. In each of the foregoing cases, the applicable margin or fee is based on the Company’s Consolidated Leverage Ratio, as defined in the Credit Facility, as of the then most recent fiscal quarter.

As of June 30, 2017 and December 31, 2016, outstanding revolving loans, which included $153 million and $119 million, respectively, of borrowings denominated in foreign currencies, accrued interest at weighted average rates of approximately 3.60% and 3.71% per annum, respectively. The term loan accrued interest at a rate of 2.73% and 2.77% as of June 30, 2017 and December 31, 2016, respectively. Letters of credit of approximately $305.6 million and $314.3 million were issued as of June 30, 2017 and December 31, 2016, respectively. As of June 30, 2017 and December 31, 2016, letters of credit fees accrued at 0.625% and 1.00% per annum, respectively, for performance standby letters of credit, and at 1.50% and 2.00% per annum, respectively, for financial standby letters of credit. Outstanding letters of credit mature at various dates and most have automatic renewal provisions, subject to prior notice of cancellation. As of June 30, 2017, total availability of $379.8 million under the 2017 Credit Facility included $150.0 million of term loans and $229.8 million of availability for revolving loans or new letters of credit. As of December 31, 2016, total availability of $405.9 million was available for revolving loans, or up to $335.7 million for new letters of credit. Revolving loan borrowing capacity included $147.4 million and $80.9 million of availability in either Canadian dollars or Mexican pesos as of June 30, 2017 and December 31, 2016, respectively. The unused facility fee as of June 30, 2017 and December 31, 2016 accrued at a rate of 0.25% and 0.40%, respectively.

The Credit Facility is guaranteed by certain subsidiaries of the Company (the “Guarantor Subsidiaries”) and the obligations under the Credit Facility are secured by substantially all of the Company’s and the Guarantor Subsidiaries’ respective assets, subject to certain exceptions. The Credit Facility requires that the Company maintain a Maximum Consolidated Leverage Ratio, as defined in the Credit Facility, of 3.50 (subject to the Acquisition Adjustment described below). The Credit Facility also requires that the Company maintain a Minimum Consolidated Interest Coverage Ratio, as defined in the Credit Facility, of 3.00. The Credit Facility provides that, for purposes of calculating the Consolidated Leverage Ratio, certain cash charges may be added back to the calculation of Consolidated EBITDA, as defined in the Credit Facility, and funded indebtedness excludes undrawn standby performance letters of credit. Additionally, notwithstanding the terms discussed above, subject to certain conditions, if a permitted acquisition or series of permitted acquisitions having consideration exceeding $50 million occurs during a fiscal quarter, the Consolidated Leverage Ratio may be temporarily increased to up to 3.75 during such fiscal quarter and the subsequent two fiscal quarters. Such right may be exercised no more than two times during the term of the Credit Facility. Subject to customary exceptions, the Credit Facility limits the borrowers’ and the Guarantor Subsidiaries’ ability to engage in certain activities, including acquisitions, mergers and consolidations, debt incurrence, investments, capital expenditures, asset sales, debt prepayments, lien incurrence and the making of distributions or repurchases of capital stock. However, distributions payable solely in capital stock are permitted. The Credit Facility provides for customary events of default and carries cross-default provisions with the Company’s other significant debt instruments, including the Company’s indemnity agreement with its surety provider, as well as customary remedies, including the acceleration of repayment of outstanding amounts and other remedies with respect to the collateral securing the Credit Facility obligations.

Other Credit Facilities. The Company has other credit facilities that support the working capital requirements of its foreign operations. Borrowings under these credit facilities, which have varying dates of maturity and are generally renewed on an annual basis, are denominated in Canadian dollars. As June 30, 2017 and December 31, 2016, maximum borrowing capacity totaled Canadian $20.0 million and $40.0 million, respectively, or approximately $15.4 million and $29.8 million, respectively. As of June 30, 2017 and December 31, 2016, outstanding borrowings totaled approximately $7.0 million and $13.4 million, respectively, and accrued interest at a weighted average rate of approximately 3.5% and 3.6%, respectively. Outstanding borrowings that are not renewed are repaid with borrowings under the Company’s senior secured credit facility. Accordingly, the carrying amounts of the Company’s borrowings under its other credit facilities, which are included within notes payable and other debt obligations in the table above, are classified within long-term debt in the Company’s consolidated balance sheets. The Company’s other credit facilities are subject to customary provisions and covenants.

Debt Guarantees and Covenants

The 4.875% Senior Notes are senior unsecured unsubordinated obligations and rank equal in right of payment with existing and future unsubordinated debt, and rank senior in right of payment to existing and future subordinated debt and are fully and unconditionally guaranteed on an unsecured, unsubordinated, joint and several basis by certain of the Company’s existing and future 100%-owned direct and indirect domestic subsidiaries that are each guarantors of the Company’s Credit Facility or other outstanding indebtedness. See Note 16 - Supplemental Guarantor Condensed Unaudited Consolidating Financial Information.

MasTec was in compliance with the provisions and covenants of its outstanding debt instruments as of June 30, 2017 and December 31, 2016.

Additional Information

As of June 30, 2017 and December 31, 2016, accrued interest payable, which is recorded within other accrued expenses in the consolidated balance sheets, totaled $8.8 million and $8.5 million, respectively. Additionally, in connection with the 2017 Credit Facility amendment, the Company paid $6.2 million in financing costs for the six month period ended June 30, 2017. For additional information pertaining to the Company’s debt instruments, including its 4.875% Senior Notes, see Note 7 - Debt in the Company’s 2016 Form 10-K.

Lease Obligations	6 Months Ended
Lease Obligations	Jun. 30, 2017
Leases [Abstract]
Lease Obligations	Note 8 - Lease Obligations Capital Leases MasTec enters into agreements that provide lease financing for machinery and equipment. The gross amount of assets held under capital leases as of June 30, 2017 and December 31, 2016, which are included within property and equipment, net, totaled $395.2 million and $294.9 million, respectively. Assets held under capital leases, net of accumulated depreciation, totaled $264.3 million and $177.5 million as of June 30, 2017 and December 31, 2016, respectively. Operating Leases In the ordinary course of business, the Company enters into non-cancelable operating leases for certain of its facility, vehicle and equipment needs, including related party leases. See Note 15 - Related Party Transactions. Rent and related expense for operating leases that have non-cancelable terms in excess of one year totaled approximately $26.6 million and $24.3 million for the three month periods ended June 30, 2017 and 2016, respectively, and totaled $52.2 million and $48.9 million for the six month periods ended June 30, 2017 and 2016, respectively. The Company also incurred rent and related expense for facilities, vehicles and equipment having original terms of one year or less totaling approximately $133.3 million and $70.7 million for the three month periods ended June 30, 2017 and 2016, respectively, and totaling $188.4 million and $117.2 million for the six month periods ended June 30, 2017 and 2016, respectively.

Stock-Based Compensation and Other Employee Benefit Plans

6 Months Ended

Jun. 30, 2017

Share-based Compensation [Abstract]

Stock-Based Compensation and Other Employee Benefit Plans

Note 9 – Stock-Based Compensation and Other Employee Benefit Plans

The Company has stock-based compensation plans, under which shares of the Company’s common stock are reserved for issuance. Under all stock-based compensation plans in effect as of June 30, 2017, including employee stock purchase plans, there were approximately 5.0 million shares available for future grant. In March 2017, the Company’s board of directors adopted the Amended and Restated 2013 Incentive Compensation Plan (the “Amended 2013 ICP”), which was effective as of January 1, 2017 and changed the amount of tax the Company can withhold for employee tax withholdings on share-based awards, as provided under ASU 2016-09. The Company adopted ASU 2016-09 as of January 1, 2017, as discussed in Note 1 - Business, Basis of Presentation and Significant Accounting Policies.

Restricted Shares

MasTec grants restricted stock awards and restricted stock units (together “restricted shares”), which are valued based on the closing market share price of MasTec common stock (the “market price”) on the date of grant. During the restriction period, holders of restricted stock awards are entitled to vote the shares. Total unearned compensation related to restricted shares as of June 30, 2017 was approximately $19.2 million, which is expected to be recognized over a weighted average period of approximately 1.4 years. The intrinsic value of restricted shares that vested, which is based on the market price on the date of vesting, totaled $0.2 million and $1.2 million for the three month periods ended June 30, 2017 and 2016, respectively, and totaled $11.7 million and $1.4 million for the six month periods ended June 30, 2017 and 2016, respectively.



Activity, restricted shares: ^(a)	Restricted Shares		Per Share Weighted Average Grant Date Fair Value
Non-vested restricted shares, as of December 31, 2016	1,970,586		$	21.61
Granted	188,843		39.44
Vested	(300,633	)	40.73
Canceled/forfeited	(17,400	)	16.57
Non-vested restricted shares, as of June 30, 2017	1,841,396		$	20.36


(a)	Includes 39,050 and 43,300 restricted stock units as of June 30, 2017 and December 31, 2016, respectively.

Stock Options

The Company previously granted options to purchase its common stock to employees and members of the Board of Directors and affiliates under various stock option plans. During 2016, all stock options that were outstanding under previous stock option grants were exercised. For the three and six month periods ended June 30, 2016, the intrinsic value of options exercised, which is based on the difference between the exercise price and the market share price of the Company’s common stock on the date of exercise, totaled $0.6 million and $1.3 million, respectively. For the three and six month periods ended June 30, 2016, proceeds from options exercised totaled $0.7 million and $2.0 million, respectively.

Employee Stock Purchase Plans

The Company has certain employee stock purchase plans (collectively, “ESPPs”) under which shares of the Company's common stock are available for purchase by eligible employees. The following table provides details pertaining to the Company’s ESPPs for the periods indicated:



	For the Six Months Ended June 30,
	2017		2016
Cash proceeds (in millions)	$	1.6	$	1.3
Common shares issued	49,502		83,680
Weighted average price per share	$	33.30	$	15.95
Weighted average per share grant date fair value	$	8.67	$	4.36

Non-Cash Stock-Based Compensation Expense

Details of non-cash stock-based compensation expense and related tax effects for the periods indicated were as follows (in millions):



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2017		2016		2017		2016
Non-cash stock-based compensation expense	$	3.4	$	3.9	$	7.2	$	7.4
Income Tax Effects:
Income tax effect of non-cash stock-based compensation	$	1.3	$	2.3	$	2.5	$	3.9
Excess tax benefit from non-cash stock-based compensation ^(a)	$	0.0	$	0.9	$	0.1	$	1.1

(a)

Excess tax benefits represent cash flows from tax deductions in excess of the tax effect of compensation expense associated with share-based payment arrangements. For the six month period ended June 30, 2017, the Company incurred a net tax deficiency of $0.1 million related to the vesting of share-based payment awards and excess tax benefits were de minimis. As discussed in Note 1 - Business, Basis of Presentation and Significant Accounting Policies, the Company adopted ASU 2016-09 effective January 1, 2017 on a prospective basis. ASU 2016-09 changed the required presentation of excess tax benefits in the consolidated statement of cash flows from financing activities to operating activities. Excess tax benefits for the comparative prior year period are classified as cash flows from financing activities.

Other Retirement Plans

6 Months Ended

Jun. 30, 2017

Multiemployer Plans [Abstract]

Other Retirement Plans

Note 10 – Other Retirement Plans

Multiemployer Plans. Certain of MasTec’s subsidiaries, including certain subsidiaries in Canada, contribute amounts to multiemployer pension and other multiemployer benefit plans and trusts, which are recorded as a component of employee wages and salaries within costs of revenue, excluding depreciation and amortization. Contributions are generally based on fixed amounts per hour per employee for employees covered under these plans. Multiemployer plan contribution rates are determined annually and assessed on a “pay-as-you-go” basis based on union employee payrolls. Union payrolls cannot be determined for future periods because the number of union employees employed at a given time, and the plans in which they may participate, vary depending upon the location and number of ongoing projects at a given time and the need for union resources in connection with those projects. Total contributions to multiemployer plans, and the related number of employees covered by these plans, including with respect to the Company’s Canadian operations, for the periods indicated were as follows:



	Multiemployer Plans
	Covered Employees		Contributions (in millions)
	Low	High	Pension		Other Multiemployer		Total
For the Three Months Ended June 30:
2017	3,669	7,057	$	28.3	$	2.7	$	31.0
2016	1,410	4,170	$	12.2	$	2.5	$	14.7
For the Six Months Ended June 30:
2017	550	7,057	$	32.0	$	5.3	$	37.3
2016	1,112	4,170	$	17.0	$	4.7	$	21.7

The fluctuations in the average number of employees covered under multiemployer plans and related contributions in the table above related primarily to timing of activity of the Company’s union resource-based projects for its oil and gas operations.

Equity	6 Months Ended
Equity	Jun. 30, 2017
Equity [Abstract]
Equity	Note 11 – Equity Accumulated Other Comprehensive Loss Accumulated other comprehensive loss is composed of unrealized foreign currency translation gains and losses, which relate primarily to fluctuations in foreign currency exchange rates of the Company’s foreign subsidiaries with a functional currency other than the U.S. dollar, and unrealized gains and losses from certain investment activities. For both the three and six month periods ended June 30, 2017 and 2016, unrealized foreign currency activity related primarily to the Company’s Canadian operations, and unrealized investment activity related to interest rate swaps associated with the Waha JVs. Share Activity No shares of the Company’s common stock have been repurchased under the Company’s 2016 share repurchase program.

Income Taxes	6 Months Ended
Income Taxes	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Note 12 - Income Taxes In determining the quarterly provision for income taxes, management uses an estimated annual effective tax rate based on forecasted annual pre-tax income, permanent tax differences, statutory tax rates and tax planning opportunities in the various jurisdictions in which the Company operates. The effect of significant discrete items is separately recognized in the quarter(s) in which they occur. As discussed in Note 1 - Business, Basis of Presentation and Significant Accounting Policies, effective January 1, 2017, the Company adopted ASU 2016-09, which changed the recognition requirements for excess tax benefits (“windfalls”) or tax deficiencies (“shortfalls”) from share-based payment awards. ASU 2016-09 requires windfalls or shortfalls to be recognized within income tax expense in the interim periods in which they occur, rather than as additional paid-in capital. Given that windfalls or shortfalls are recognized in income tax expense in the periods in which they occur, they are not included when estimating annual effective tax rates. The tax effect related to the vesting of share-based payment awards did not have a significant effect on the Company’s consolidated effective tax rate for the three and six month periods ended June 30, 2017. As of June 30, 2017, the Company had $252.8 million of long-term deferred tax liabilities. As of December 31, 2016, current deferred tax assets, net, totaled $11.8 million and long-term deferred tax liabilities, net, totaled $178.4 million. In addition, as of June 30, 2017 and December 31, 2016, accrued income and other taxes payable, which are included within other accrued expenses, totaled $16.7 million and $40.3 million, respectively. The Company adopted Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes (“ASU 2015-17”), which changed the classification requirements for deferred tax assets and liabilities, effective January 1, 2017. ASU 2015-17 requires long-term classification of all deferred tax assets and liabilities, rather than separately classifying deferred tax assets and liabilities based on their net current and non-current amounts, as was required under the previous guidance. The Company adopted ASU 2015-17 on a prospective basis, therefore prior periods were not adjusted to conform to the current period presentation. The adoption of ASU 2015-17 did not have had a material effect on the consolidated financial statements.

Segments and Related Information

6 Months Ended

Jun. 30, 2017

Segment Reporting [Abstract]

Segments and Related Information

Note 13 - Segments and Related Information

Segment Discussion

MasTec manages its operations under five operating segments, which represent MasTec’s five reportable segments: (1) Communications; (2) Oil and Gas; (3) Electrical Transmission; (4) Power Generation and Industrial and (5) Other. This structure is generally focused on broad end-user markets for MasTec’s labor-based construction services. All five reportable segments derive their revenue from the engineering, installation and maintenance of infrastructure, primarily in North America.

The Communications segment performs engineering, construction, maintenance and customer fulfillment activities related to communications infrastructure primarily for wireless and wireline/fiber communications and install-to-the-home customers, and, to a lesser extent, infrastructure for utilities, among others. MasTec performs engineering, construction and maintenance services on oil and natural gas pipelines and processing facilities for the energy and utilities industries through its Oil and Gas segment. The Electrical Transmission segment primarily serves the energy and utility industries through the engineering, construction and maintenance of electrical transmission lines and substations. The Power Generation and Industrial segment primarily serves energy, utility and other end-markets through the installation and construction of conventional and renewable power facilities, related electrical transmission infrastructure, ethanol/biofuel facilities and various types of industrial infrastructure. The Other segment includes equity investees, the services of which vary from those provided by the Company’s four primary segments, as well as other small business units that perform construction and other services for a variety of international end-markets.

Earnings before interest, taxes, depreciation and amortization (“EBITDA”) is the measure of profitability used by management to manage its segments and, accordingly, in its segment reporting. As appropriate, the Company supplements the reporting of consolidated financial information determined in accordance with U.S. GAAP with certain non-U.S. GAAP financial measures, including EBITDA. The Company believes these non-U.S. GAAP measures provide meaningful information and help investors understand the Company’s financial results and assess its prospects for future performance. The Company uses EBITDA to evaluate its performance, both internally and as compared with its peers, because it excludes certain items that may not be indicative of the Company’s core operating results for its reportable segments, as well as items that can vary widely across different industries or among companies within the same industry, and for non-cash stock-based compensation expense, can also be subject to volatility from changes in the market price per share of our common stock or variations in the value of shares granted. Segment EBITDA is calculated in a manner consistent with consolidated EBITDA.

For the six month period ended June 30, 2017, Other segment EBITDA included previously disclosed first quarter project losses of $7.0 million from a proportionately consolidated non-controlled Canadian joint venture, which is managed by a third party, and for which we have minimal direct construction involvement. For the six month period ended June 30, 2016, Oil and Gas and Electrical Transmission segment EBITDA included first quarter project losses of $13.5 million and $15.1 million, respectively.

Summarized financial information for MasTec’s reportable segments is presented and reconciled to consolidated financial information for total MasTec in the following tables (in millions):



	For the Three Months Ended June 30,						For the Six Months Ended June 30,
Revenue:	2017			2016			2017			2016
Communications ^(a)	$	592.2		$	592.2		$	1,151.7		$	1,103.8
Oil and Gas	1,140.4			425.6			1,596.2			718.4
Electrical Transmission	96.6			95.6			195.4			181.9
Power Generation and Industrial	60.7			119.7			107.3			201.1
Other	1.9			3.9			3.6			7.3
Eliminations	(1.6		)	(4.6		)	(5.8		)	(5.9		)
Consolidated revenue	$	1,890.2		$	1,232.4		$	3,048.4		$	2,206.6


(a)	Revenue generated primarily by utilities customers represented 11.5% and 11.0% of Communications segment revenue for the three month periods ended June 30, 2017 and 2016, respectively, and represented 12.4% and 10.7% for the six month periods ended June 30, 2017 and 2016, respectively.



	For the Three Months Ended June 30,						For the Six Months Ended June 30,
EBITDA:	2017			2016			2017			2016
Communications	$	59.5		$	66.4		$	107.8		$	128.1
Oil and Gas	154.0			53.6			247.9			69.8
Electrical Transmission	3.5			(9.9		)	6.7			(33.7		)
Power Generation and Industrial	4.7			4.8			5.6			7.7
Other	6.8			0.3			1.5			0.5
Corporate	(29.6		)	(19.9		)	(47.1		)	(30.9		)
Consolidated EBITDA	$	198.9		$	95.3		$	322.4		$	141.5



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
Depreciation and Amortization:	2017		2016		2017		2016
Communications	$	13.5	$	12.4	$	25.5	$	24.6
Oil and Gas	23.2		19.3		45.1		37.5
Electrical Transmission	5.7		5.8		11.4		11.0
Power Generation and Industrial	1.4		1.5		2.9		3.1
Other	0.0		0.0		0.1		0.0
Corporate	1.6		1.7		3.3		3.5
Consolidated depreciation and amortization	$	45.4	$	40.7	$	88.3	$	79.7

The following table, which may contain slight summation differences due to rounding, presents a reconciliation of consolidated income before income taxes to EBITDA (in millions):



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
EBITDA Reconciliation:	2017		2016		2017		2016
Income before income taxes	$	138.8	$	42.0	$	206.8	$	37.1
Plus:
Interest expense, net	14.8		12.6		27.4		24.8
Depreciation and amortization	45.4		40.7		88.3		79.7
Consolidated EBITDA	$	198.9	$	95.3	$	322.4	$	141.5

Foreign Operations. MasTec operates in North America, primarily in the United States and Canada, and, to a lesser extent, in Mexico. For the three month periods ended June 30, 2017 and 2016, revenue of $1.8 billion and $1.2 billion, respectively, was derived from U.S. operations, and revenue of $40.5 million and $65.5 million, respectively, was derived from foreign operations, primarily in Canada. For the six month periods ended June 30, 2017 and 2016, revenue of $2.9 billion and $2.1 billion, respectively, was derived from U.S. operations, and revenue of $99.7 million and $149.0 million, respectively, was derived from foreign operations, primarily in Canada. The majority of the Company’s foreign operations during the three and six month periods ended June 30, 2017 and 2016 were in the Company’s Oil and Gas segment. Long-lived assets held in the U.S. included property and equipment, net, of $583.8 million and $475.3 million as of June 30, 2017 and December 31, 2016, respectively, and, for the Company’s businesses in foreign countries, primarily in Canada, totaled $64.7 million and $73.8 million, respectively. Intangible assets and goodwill, net, related to the Company’s U.S. operations totaled approximately $1.1 billion as of both June 30, 2017 and December 31, 2016, and, for the Company’s businesses in foreign countries, primarily in Canada, totaled approximately $110.6 million and $107.8 million as of June 30, 2017 and December 31, 2016, respectively. Amounts due from customers from which foreign revenue was derived accounted for approximately 5% and 8%, respectively, of the Company’s consolidated net accounts receivable position as of June 30, 2017 and December 31, 2016, which represents accounts receivable, net, less BIEC.

Significant Customers

Revenue concentration information for significant customers as a percentage of total consolidated revenue was as follows:



	For the Three Months Ended June 30,		For the Six Months Ended June 30,
Customer:	2017	2016	2017	2016
Energy Transfer affiliates ^(a)	47%	22%	35%	20%
AT&T (including DIRECTV^®) ^(b)	22%	36%	27%	37%


(a)	The Company's relationship with Energy Transfer affiliates is based upon various construction contracts for pipeline activities with Energy Transfer Partners L.P., and their subsidiaries and affiliates, all of which are consolidated by Energy Transfer Equity, L.P. Revenue from Energy Transfer affiliates is included in the Oil and Gas segment.

(b)

The Company’s relationship with AT&T is based upon multiple separate master service and other service agreements, including for installation and maintenance services, as well as construction/installation contracts for AT&T’s: (i) wireless business; (ii) wireline/fiber businesses; and (iii) various install-to-the-home businesses, including DIRECTV®. Revenue from AT&T is included in the Communications segment.

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 14 - Commitments and Contingencies MasTec is subject to a variety of legal cases, claims and other disputes that arise from time to time in the ordinary course of its business. See Note 14 - Commitments and Contingencies in the Company’s 2016 Form 10-K for additional information. MasTec cannot provide assurance that it will be successful in recovering all or any of the potential damages it has claimed or in defending claims against the Company. The outcome of such cases, claims and disputes cannot be predicted with certainty and an unfavorable resolution of one or more of them could have a material adverse effect on the Company’s business, financial condition, results of operations and cash flows. Other Commitments and Contingencies Leases. In the ordinary course of business, the Company enters into non-cancelable operating leases for certain of its facility, vehicle and equipment needs, including related party leases. See Note 8 - Lease Obligations and Note 15 - Related Party Transactions. Letters of Credit. In the ordinary course of business, the Company is required to post letters of credit for its insurance carriers, surety bond providers and in support of performance under certain contracts as well as certain obligations associated with the Company’s cost and equity investees, including its variable interest entities. Such letters of credit are generally issued by a bank or similar financial institution. The letter of credit commits the issuer to pay specified amounts to the holder of the letter of credit under certain conditions. If this were to occur, the Company would be required to reimburse the issuer of the letter of credit, which, depending upon the circumstances, could result in a charge to earnings. As of June 30, 2017 and December 31, 2016, there were $305.6 million and $314.3 million, respectively, of letters of credit issued under the Company’s Credit Facility. The Company is not aware of material claims relating to its outstanding letters of credit as of June 30, 2017 or December 31, 2016. Performance and Payment Bonds. In the ordinary course of business, MasTec is required by certain customers to provide performance and payment bonds for contractual commitments related to projects in process. These bonds provide a guarantee to the customer that the Company will perform under the terms of a contract and that the Company will pay subcontractors and vendors. If the Company fails to perform under a contract or to pay subcontractors and vendors, the customer may demand that the surety make payments or provide services under the bond. The Company must reimburse the surety for expenses or outlays it incurs. As of June 30, 2017 and December 31, 2016, outstanding performance and payment bonds totaled $50.9 million and $72.9 million, respectively, and estimated costs to complete projects secured by these bonds totaled $9.6 million and $9.5 million as of June 30, 2017 and December 31, 2016, respectively. These amounts do not include performance and payment bonds associated with the Company’s equity investees. Cost and Equity Investees and Other Entities. The Company holds a 35% undivided interest in a proportionately consolidated non-controlled Canadian contractual joint venture that was underway when the Company acquired Pacer in 2014, whose sole activity involves the construction of a bridge, a business in which the Company does not otherwise engage. This joint venture, which is managed by a third party, and for which the Company has minimal direct construction involvement, automatically terminates upon completion of the project. The Company also holds undivided interests of 85%, 85% and 90%, respectively, in three proportionately consolidated non-controlled contractual joint ventures that provide infrastructure construction services for electrical transmission projects. Income and/or losses incurred by these joint ventures are generally shared proportionally by the respective joint venture members, with the members of the joint ventures jointly and severally liable for all of the obligations of the joint venture. The respective joint venture agreements provide that each joint venture partner indemnify the other party for any liabilities incurred by such joint venture in excess of its ratable portion of such liabilities. Thus, it is possible that the Company could be required to pay or perform obligations in excess of its share if the other joint venture partners fail or refuse to pay or perform their respective share of the obligations. As of June 30, 2017, the Company was not aware of circumstances that would reasonably lead to material future claims against it in connection with these arrangements. The Company has other investment arrangements, as discussed in Note 4 - Fair Value of Financial Instruments and Note 15 - Related Party Transactions. From time to time, the Company may incur costs or provide financing, performance, financial and/or other guarantees to or in connection with its investees. Self-Insurance. MasTec maintains insurance policies for workers’ compensation, general liability and automobile liability, which are subject to per claim deductibles. The Company also maintains excess umbrella coverage. As of June 30, 2017 and December 31, 2016, MasTec’s liability for unpaid claims and associated expenses, including incurred but not reported losses related to these policies, totaled $94.2 million and $85.8 million, respectively, of which $59.5 million and $55.2 million, respectively, were reflected within other long-term liabilities in the consolidated balance sheets. MasTec also maintains an insurance policy with respect to employee group medical claims, which is subject to annual per employee maximum losses. MasTec’s liability for employee group medical claims totaled $3.0 million and $2.6 million as of June 30, 2017 and December 31, 2016, respectively. The Company is required to post letters of credit and provide cash collateral to certain of its insurance carriers and to provide surety bonds in certain states. Insurance-related letters of credit for the Company’s workers’ compensation, general liability and automobile liability policies amounted to $85.1 million as of both June 30, 2017 and December 31, 2016, respectively. In addition, cash collateral deposited with insurance carriers, which is included within other long-term assets, amounted to $1.5 million for these policies as of both June 30, 2017 and December 31, 2016. Outstanding surety bonds related to workers’ compensation self-insurance programs amounted to $13.5 million as of both June 30, 2017 and December 31, 2016. Employment Agreements. The Company has employment agreements with certain executives and other employees, which provide for compensation and certain other benefits and for severance payments under certain circumstances. Certain employment agreements also contain clauses that become effective upon a change in control of the Company. Upon the occurrence of any of the defined events in the various employment agreements, the Company would be obligated to pay certain amounts to the relevant employees, which vary with the level of the employees’ respective responsibility. Collective Bargaining Agreements and Multiemployer Plans. As discussed in Note 10 - Other Retirement Plans, certain of MasTec’s subsidiaries are party to various collective bargaining agreements with unions representing certain of their employees, which require the Company to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to multiemployer pension and other multiemployer benefits plans and trusts. The Employee Retirement Income Security Act of 1974, as amended by the Multiemployer Pension Plan Amendments Act of 1980 (collectively, “ERISA”), which governs U.S.-registered multiemployer pension plans, subjects employers to substantial liabilities in the event of the employer’s complete or partial withdrawal from, or upon termination of, such plans. The Company currently contributes, and in the past has contributed to, plans that are underfunded, and, therefore, could have potential liability associated with a voluntary or involuntary withdrawal from, or termination of, these plans. Other than the Company’s 2011 withdrawal from the Central States Southeast and Southwest Areas Pension Fund (“Central States”) and certain other underfunded plans, as described in the Company’s 2016 Form 10-K, the Company does not have plans to withdraw from, and is not aware of circumstances that would reasonably lead to material claims against it in connection with these plans. However, there can be no assurance that the Company will not be assessed liabilities in the future. Based upon the information available to the Company from plan administrators as of June 30, 2017, several of the multiemployer pension plans in which it participates are underfunded and, as a result, the Company could be required to increase its contributions, including in the form of a surcharge on future benefit contributions. The amount of additional funds the Company may be obligated to contribute in the future cannot be estimated, as these amounts are based on future levels of work of the union employees covered by these plans, investment returns and the level of underfunding of such plans. Indemnities. The Company generally indemnifies its customers for the services it provides under its contracts, as well as other specified liabilities, which may subject the Company to indemnity claims, liabilities and related litigation. As of June 30, 2017 and December 31, 2016, the Company was not aware of any material asserted or unasserted claims in connection with these indemnity obligations. Other Guarantees. In the ordinary course of its business, from time to time, MasTec guarantees the obligations of its subsidiaries, including obligations under certain contracts with customers, certain lease obligations and in some states, obligations in connection with obtaining contractors’ licenses. MasTec has also issued performance and other guarantees in connection with certain of its equity investees. MasTec also generally warrants the work it performs for a one to two year period following substantial completion of a project. Much of the work performed by the Company is evaluated for defects shortly after the work is completed. Accrued warranty claims are, and historically have been, de minimis. However, if warranty claims occur, the Company could be required to repair or replace warrantied items, or, if customers elect to repair or replace the warrantied item using the services of another provider, the Company could be required to pay for the cost of the repair or replacement. Concentrations of Risk. The Company had approximately 375 customers for the six month period ended June 30, 2017. As of June 30, 2017 and December 31, 2016, one customer accounted for approximately 48% and 24%, respectively, of the Company’s consolidated net accounts receivable position, which represents accounts receivable, net, less BIEC. As of June 30, 2017 and December 31, 2016, a separate customer accounted for approximately 11% and 17%, respectively, of the Company’s consolidated net accounts receivable position. In addition, the Company derived 84% and 76%, respectively, of its revenue from its top ten customers for the three month periods ended June 30, 2017 and 2016, and derived 79% and 74% of its revenues, respectively, from its top ten customers for the six month periods ended June 30, 2017 and 2016.

Related Party Transactions	6 Months Ended
Related Party Transactions	Jun. 30, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Note 15 - Related Party Transactions For the three month periods ended June 30, 2017 and 2016, revenue recognized by the Company’s Pacer subsidiary for work performed for a contractual joint venture in which it holds a 35% undivided interest totaled $0.2 million and $0.3 million, respectively, and for the six month periods ended June 30, 2017 and 2016, totaled $0.3 million and $0.6 million, respectively. As of June 30, 2017 and December 31, 2016, receivables from this contractual joint venture totaled $0.8 million and $0.7 million, respectively. Related performance guarantees, which are based on the original full contract value, as of both June 30, 2017 and December 31, 2016, totaled Canadian $132.1 million (or approximately $101.9 million and $98.3 million, respectively). In connection with this contractual joint venture, the Company provided project-related financing of $2.3 million and $3.1 million, respectively, for the three and six month periods ended June 30, 2017, and $1.4 million and $4.9 million, respectively, for the three and six month periods ended June 30, 2016. As of June 30, 2017, there were no additional amounts committed to this entity. In connection with an April 2017 acquisition, the Company acquired a 40% interest in an entity, valued at $0.4 million. The Company has a subcontracting arrangement with this entity. For the three month period ended June 30, 2017, the Company incurred $0.2 million of expenses under this subcontracting arrangement, and associated amounts payable as of June 30, 2017 totaled $0.1 million. Amounts advanced to this entity during the second quarter of 2017, which amount was outstanding as of June 30, 2017, totaled $0.3 million. Additionally, during the second quarter of 2017, in connection with this acquisition, the Company made payments of $3.8 million under a vendor financing arrangement to an entity that is owned by a member of subsidiary management. As of June 30, 2017, related payables totaled approximately $1.4 million. During the second quarter of 2017, the Company committed to invest $2.0 million in connection with its expected approximate 4% interest in a special purpose acquisition corporation, focusing on transactions in the telecommunications industry, upon completion of its initial public offering, which occurred in the third quarter of 2017. Upon completion of the offering, José R. Mas, MasTec’s Chief Executive Officer, became a director of this corporation and another employee of the Company is this corporation’s Chief Executive Officer. MasTec purchases, rents and leases equipment used in its business from a number of different vendors on a non-exclusive basis, including CCI, in which the Company has a cost method investment. Juan Carlos Mas, who is the brother of Jorge Mas, Chairman of MasTec’s Board of Directors, and José R. Mas, serves as the chairman of CCI. For the three month periods ended June 30, 2017 and 2016, MasTec paid CCI approximately $11.0 million and $2.8 million, respectively, for equipment supplies, rentals, leases and servicing. For the six month periods ended June 30, 2017 and 2016, MasTec paid CCI approximately $12.0 million and $3.6 million, respectively, net of rebates. As of June 30, 2017 and December 31, 2016, related payables totaled approximately $10.9 million and $1.5 million, respectively. MasTec has a subcontracting arrangement with an entity for the performance of construction services, the minority owners of which include an entity controlled by Jorge Mas and José R. Mas, along with two members of management of a MasTec subsidiary. For the three month periods ended June 30, 2017 and 2016, MasTec incurred $15.0 million and $1.8 million, respectively, of expenses under this subcontracting arrangement, and for the six month periods ended June 30, 2017 and 2016, MasTec incurred $15.5 million and $3.3 million, respectively. As of June 30, 2017 and December 31, 2016, related amounts payable totaled $6.5 million and $0.1 million, respectively. MasTec leases employees to a customer in which Jorge Mas and José R. Mas own a majority interest. For both three month periods ended June 30, 2017 and 2016, MasTec charged approximately $0.2 million to this customer, and for both the six month periods ended June 30, 2017 and 2016, charged $0.4 million. As of both June 30, 2017 and December 31, 2016, outstanding receivables from employee leasing arrangements with this customer totaled $0.2 million. The Company also provides satellite communication services to this customer. For both three month periods ended June 30, 2017 and 2016, revenue from satellite communication services provided to this customer totaled approximately $0.2 million, and for both the six month periods ended June 30, 2017 and 2016, satellite communication revenues totaled $0.4 million. As of June 30, 2017 and December 31, 2016, receivables from this arrangement totaled approximately $0.3 million and $0.4 million, respectively. MasTec has a leasing arrangement with a third party that leases an aircraft from a Company owned by Jorge Mas. For the three month periods ended June 30, 2017 and 2016, MasTec paid $0.5 million and $0.6 million, respectively, under this leasing arrangement, and for the six month periods ended June 30, 2017 and 2016, MasTec paid $1.0 million and $1.3 million, respectively. As of June 30, 2017, there were no related amounts payable, and, as of December 31, 2016, related amounts payable were de minimis. For the three month periods ended June 30, 2017 and 2016, related party lease payments for operational facilities and equipment, which are primarily associated with members of subsidiary management, totaled approximately $14.4 million and $9.9 million, respectively, and for the six month periods ended June 30, 2017 and 2016, related party lease payments totaled approximately $27.1 million and $19.1 million, respectively. Payables associated with related party leases totaled approximately $0.2 million and $0.3 million as of June 30, 2017 and December 31, 2016, respectively. Additionally, payments for various types of supplies and services, including ancillary construction services, project-related site restoration and marketing and business development activities associated with members of subsidiary management totaled approximately $7.9 million and $3.6 million for the three month periods ended June 30, 2017 and 2016, respectively, and totaled $14.5 million and $6.8 million for the six month periods ended June 30, 2017 and 2016, respectively. As of June 30, 2017 and December 31, 2016, associated amounts payable totaled approximately $3.9 million and $3.7 million, respectively. Non-controlling interests in entities consolidated by the Company represent ownership interests held by certain members of management of several of the Company’s subsidiaries, primarily in our Oil and Gas segment, and the Company has a subcontracting arrangement with one of these entities for the performance of ancillary oil and gas construction services, which transactions are eliminated in consolidation. The Company made distributions of earnings of $1.3 million in the first quarter of 2017 to holders of its non-controlling interests. Split Dollar Agreements MasTec has split dollar insurance agreements with each of José R. Mas and Jorge Mas. The Company paid $0.7 million and $0.5 million in the second quarter of 2017 in connection with the agreements for José R. Mas and Jorge Mas, respectively. The Company paid $0.7 million and $0.5 million in the second quarter of 2016 in connection with the agreements for José R. Mas and Jorge Mas, respectively. As of June 30, 2017 and December 31, 2016, life insurance assets associated with these agreements totaled $16.0 million and $14.8 million, respectively, which amount is included within other long-term assets.

Supplemental Guarantor Financial Information

6 Months Ended

Jun. 30, 2017

Condensed Unaudited Financial Statements, Supplemental Guarantor Information [Abstract]

Supplemental Guarantor Financial Information

Note 16 – Supplemental Guarantor Condensed Unaudited Consolidating Financial Information

The 4.875% Senior Notes are fully and unconditionally guaranteed on an unsecured, unsubordinated, joint and several basis by certain of the Company’s existing and future 100%-owned direct and indirect domestic subsidiaries that are each guarantors of the Credit Facility or other outstanding indebtedness (the “Guarantor Subsidiaries”). The Company’s subsidiaries organized outside of the United States and certain domestic subsidiaries (collectively, the “Non-Guarantor Subsidiaries”) do not guarantee these notes. A Guarantor Subsidiary’s guarantee is subject to release in certain customary circumstances, including upon the sale of a majority of the capital stock or substantially all of the assets of such Guarantor Subsidiary; if the Guarantor Subsidiary’s guarantee under the Company’s Credit Facility and other indebtedness is released or discharged (other than due to payment under such guarantee); or when the requirements for legal defeasance are satisfied or the obligations are discharged in accordance with the related indentures.

The following supplemental financial information sets forth the condensed unaudited consolidating balance sheets and the condensed unaudited consolidating statements of operations and comprehensive income (loss) and cash flows for MasTec, Inc., the Guarantor Subsidiaries on a combined basis, the Non-Guarantor Subsidiaries on a combined basis and the eliminations necessary to arrive at the information for the Company as reported on a consolidated basis. Eliminations represent adjustments to eliminate investments in subsidiaries and intercompany balances and transactions between or among MasTec, Inc., the Guarantor Subsidiaries and the Non-Guarantor Subsidiaries. Investments in subsidiaries are accounted for using the equity method for this presentation.

CONDENSED UNAUDITED CONSOLIDATING STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (in millions)



For the Three Months Ended June 30, 2017	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	1,818.1		$	122.9		$	(50.8	)	$	1,890.2
Costs of revenue, excluding depreciation and amortization	—			1,566.3			110.8			(50.8		)	1,626.3
Depreciation and amortization	—			37.1			8.3			—			45.4
General and administrative expenses	0.6			66.5			3.7			—			70.8
Interest expense (income), net	—			30.4			(15.6		)	—			14.8
Equity in earnings of unconsolidated affiliates	—			—			(6.1		)	—			(6.1		)
Other (income) expense, net	—			(5.3		)	5.4			—			0.1
(Loss) income before income taxes	$	(0.6	)	$	123.1		$	16.3		$	—		$	138.8
Benefit from (provision for) income taxes	0.2			(44.7		)	(10.9		)	—			(55.4		)
Net (loss) income before equity in income from subsidiaries	$	(0.4	)	$	78.4		$	5.4		$	—		$	83.3
Equity in income from subsidiaries, net of tax	82.1			—			—			(82.1		)	—
Net income (loss)	$	81.7		$	78.4		$	5.4		$	(82.1	)	$	83.3
Net income attributable to non-controlling interests	—			—			1.7			—			1.7
Net income (loss) attributable to MasTec, Inc.	$	81.7		$	78.4		$	3.7		$	(82.1	)	$	81.7
Comprehensive income (loss)	$	79.5		$	78.4		$	3.2		$	(79.9	)	$	81.2



For the Three Months Ended June 30, 2016	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	1,149.4		$	93.5		$	(10.5	)	$	1,232.4
Costs of revenue, excluding depreciation and amortization	—			995.0			83.7			(10.5		)	1,068.2
Depreciation and amortization	—			31.7			9.0			—			40.7
General and administrative expenses	0.6			61.5			5.8			—			67.9
Interest expense (income), net	—			27.8			(15.2		)	—			12.6
Equity in earnings of unconsolidated affiliates	—			—			(0.5		)	—			(0.5		)
Other expense (income), net	—			1.8			(0.3		)	—			1.5
(Loss) income before income taxes	$	(0.6	)	$	31.6		$	11.0		$	—		$	42.0
Benefit from (provision for) income taxes	0.2			(12.6		)	(5.2		)	—			(17.6		)
Net (loss) income before equity in income from subsidiaries	$	(0.4	)	$	19.0		$	5.8		$	—		$	24.4
Equity in income from subsidiaries, net of tax	24.4			—			—			(24.4		)	—
Net income (loss)	$	24.0		$	19.0		$	5.8		$	(24.4	)	$	24.4
Net income attributable to non-controlling interests	—			—			0.4			—			0.4
Net income (loss) attributable to MasTec, Inc.	$	24.0		$	19.0		$	5.4		$	(24.4	)	$	24.1
Comprehensive income (loss)	$	19.8		$	19.0		$	1.4		$	(20.1	)	$	20.1

CONDENSED UNAUDITED CONSOLIDATING STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (in millions)



For the Six Months Ended June 30, 2017	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	2,903.2		$	217.0		$	(71.8	)	$	3,048.4
Costs of revenue, excluding depreciation and amortization	—			2,457.4			211.9			(71.8		)	2,597.5
Depreciation and amortization	—			71.1			17.2			—			88.3
General and administrative expenses	1.2			126.0			8.4			—			135.6
Interest expense (income), net	—			58.3			(30.9		)	—			27.4
Equity in earnings of unconsolidated affiliates	—			—			(7.7		)	—			(7.7		)
Other (income) expense , net	—			(5.3		)	5.9			—			0.6
(Loss) income before income taxes	$	(1.2	)	$	195.7		$	12.3		$	—		$	206.8
Benefit from (provision for) income taxes	0.4			(71.3		)	(11.9		)	—			(82.8		)
Net (loss) income before equity in income from subsidiaries	$	(0.8	)	$	124.4		$	0.4		$	—		$	124.0
Equity in income from subsidiaries, net of tax	123.4			—			—			(123.4		)	—
Net income (loss)	$	122.6		$	124.4		$	0.4		$	(123.4	)	$	124.0
Net income attributable to non-controlling interests	—			—			1.3			—			1.3
Net income (loss) attributable to MasTec, Inc.	$	122.6		$	124.4		$	(1.0	)	$	(123.4	)	$	122.6
Comprehensive income (loss)	$	122.3		$	124.4		$	—		$	(123.1	)	$	123.6



For the Six Months Ended June 30, 2016	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	2,027.7		$	189.5		$	(10.6	)	$	2,206.6
Costs of revenue, excluding depreciation and amortization	—			1,772.3			190.9			(10.6		)	1,952.6
Depreciation and amortization	—			63.0			16.7			—			79.7
General and administrative expenses	1.2			111.5			15.2			—			127.9
Interest expense (income), net	—			55.2			(30.4		)	—			24.8
Equity in earnings of unconsolidated affiliates	—			—			(3.6		)	—			(3.6		)
Other income, net	—			(9.4		)	(2.4		)	—			(11.8		)
(Loss) income before income taxes	$	(1.2	)	$	35.1		$	3.1		$	—		$	37.1
Benefit from (provision for) income taxes	0.5			(14.0		)	(2.0		)	—			(15.5		)
Net (loss) income before equity in income from subsidiaries	$	(0.7	)	$	21.1		$	1.1		$	—		$	21.6
Equity in income from subsidiaries, net of tax	22.1			—			—			(22.1		)	—
Net income (loss)	$	21.4		$	21.1		$	1.1		$	(22.1	)	$	21.6
Net income attributable to non-controlling interests	—			—			0.2			—			0.2
Net income (loss) attributable to MasTec, Inc.	$	21.4		$	21.1		$	0.9		$	(22.1	)	$	21.4
Comprehensive income (loss)	$	14.7		$	21.1		$	(5.6	)	$	(15.4	)	$	14.8

CONDENSED UNAUDITED CONSOLIDATING BALANCE SHEETS (in millions)



As of June 30, 2017	MasTec, Inc.		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Eliminations			Consolidated MasTec, Inc.
Assets
Total current assets	$	—	$	1,649.5	$	212.8	$	(71.6	)	$	1,790.7
Property and equipment, net	—		556.1		92.4		—			648.5
Goodwill and other intangible assets, net	—		1,086.4		139.8		—			1,226.2
Investments in and advances to consolidated affiliates, net	1,212.9		806.2		749.0		(2,768.1		)	—
Other long-term assets	13.1		23.0		122.0		—			158.1
Total assets	$	1,226.0	$	4,121.2	$	1,316.0	$	(2,839.7	)	$	3,823.5
Liabilities and equity
Total current liabilities	$	—	$	902.4	$	97.9	$	(71.6	)	$	928.7
Long-term debt	—		1,299.5		14.4		—			1,313.9
Other long-term liabilities	—		335.6		12.1		—			347.7
Total liabilities	$	—	$	2,537.5	$	124.4	$	(71.6	)	$	2,590.3
Total equity	$	1,226.0	$	1,583.7	$	1,191.6	$	(2,768.1	)	$	1,233.2
Total liabilities and equity	$	1,226.0	$	4,121.2	$	1,316.0	$	(2,839.7	)	$	3,823.5



As of December 31, 2016	MasTec, Inc.		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Eliminations			Consolidated MasTec, Inc.
Assets
Total current assets	$	—	$	1,256.3	$	175.8	$	(29.6	)	$	1,402.5
Property and equipment, net	—		456.6		92.5		—			549.1
Goodwill and other intangible assets, net	—		1,037.4		138.2		—			1,175.6
Investments in and advances to consolidated affiliates, net	1,083.9		625.9		861.2		(2,571.0		)	—
Other long-term assets	12.6		25.3		18.0		—			55.9
Total assets	$	1,096.5	$	3,401.5	$	1,285.7	$	(2,600.6	)	$	3,183.1
Liabilities and equity
Total current liabilities	$	—	$	759.7	$	109.9	$	(29.6	)	$	840.0
Long-term debt	—		938.7		22.7		—			961.4
Other long-term liabilities	—		256.2		21.9		—			278.1
Total liabilities	$	—	$	1,954.6	$	154.5	$	(29.6	)	$	2,079.5
Total equity	$	1,096.5	$	1,446.9	$	1,131.2	$	(2,571.0	)	$	1,103.6
Total liabilities and equity	$	1,096.5	$	3,401.5	$	1,285.7	$	(2,600.6	)	$	3,183.1

CONDENSED UNAUDITED CONSOLIDATING STATEMENTS OF CASH FLOWS (in millions)



For the Six Months Ended June 30, 2017	MasTec, Inc.		Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations		Consolidated MasTec, Inc.
Net cash (used in) operating activities	$	—	$	(52.9	)	$	(35.1	)	$	—	$	(88.0	)
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	—		(37.4		)	—			—		(37.4		)
Capital expenditures	—		(46.8		)	(10.1		)	—		(56.9		)
Proceeds from sale of property and equipment	—		6.8			0.6			—		7.4
Payments for other investments	—		(1.2		)	(73.3		)	—		(74.5		)
Proceeds from other investments	—		—			12.1			—		12.1
Net cash used in investing activities	$	—	$	(78.6	)	$	(70.7	)	$	—	$	(149.3	)
Cash flows from financing activities:
Proceeds from credit facilities	—		1,141.2			12.0			—		1,153.2
Repayments of credit facilities	—		(850.2		)	(18.9		)	—		(869.1		)
Repayments of other borrowings and capital lease obligations	—		(35.8		)	(5.3		)	—		(41.1		)
Payments of acquisition-related contingent consideration	—		(18.8		)	—			—		(18.8		)
Distributions to non-controlling interests	—		—			(1.3		)	—		(1.3		)
Proceeds from stock-based awards, net	0.0		0.0			0.0			—		0.0
Other financing activities, net	—		(6.2		)	—			—		(6.2		)
Net financing activities and advances (to) from consolidated affiliates	—		(115.5		)	115.5			—		—
Net cash provided by financing activities	$	—	$	114.7		$	101.9		$	—	$	216.6
Effect of currency translation on cash	—		—			0.1			—		0.1
Net (decrease) increase in cash and cash equivalents	$	—	$	(16.8	)	$	(3.7	)	$	—	$	(20.5	)
Cash and cash equivalents - beginning of period	$	—	$	28.3		$	10.5		$	—	$	38.8
Cash and cash equivalents - end of period	$	—	$	11.4		$	6.8		$	—	$	18.2



For the Six Months Ended June 30, 2016	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations		Consolidated MasTec, Inc.
Net cash (used in) provided by operating activities	$	—		$	(30.2	)	$	58.7		$	—	$	28.5
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	—			(4.1		)	—			—		(4.1		)
Capital expenditures	—			(61.3		)	(2.6		)	—		(63.9		)
Proceeds from sale of property and equipment	—			9.1			1.0			—		10.1
Payments for other investments	—			(1.2		)	(1.5		)	—		(2.7		)
Proceeds from other investments	—			0.7			—			—		0.7
Net cash used in investing activities	$	—		$	(56.8	)	$	(3.1	)	$	—	$	(59.9	)
Cash flows from financing activities:
Proceeds from credit facilities	—			625.1			59.2			—		684.3
Repayments of credit facilities	—			(539.1		)	(65.5		)	—		(604.6		)
Repayments of other borrowings and capital lease obligations	—			(25.5		)	(8.0		)	—		(33.5		)
Payments of acquisition-related contingent consideration	—			(14.6		)	—			—		(14.6		)
Proceeds from (payments for) stock-based awards, net	3.3			(0.3		)	0.3			—		3.3
Other financing activities, net	—			1.1			—			—		1.1
Net financing activities and advances (to) from consolidated affiliates	(3.3		)	37.2			(33.9		)	—		—
Net cash provided by (used in) financing activities	$	—		$	83.9		$	(47.9	)	$	—	$	36.0
Effect of currency translation on cash	—			—			(0.9		)	—		(0.9		)
Net (decrease) increase in cash and cash equivalents	$	—		$	(3.1	)	$	6.8		$	—	$	3.7
Cash and cash equivalents - beginning of period	$	—		$	4.8		$	0.2		$	—	$	5.0
Cash and cash equivalents - end of period	$	—		$	1.7		$	7.0		$	—	$	8.7

Business, Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and with the instructions for Form 10-Q and Rule 10-01 of Regulation S-X. Pursuant to these rules and regulations, certain information and footnote disclosures normally included in the annual audited consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. The accompanying condensed consolidated balance sheet as of December 31, 2016 is derived from the Company’s audited financial statements as of that date. Because certain information and footnote disclosures have been condensed or omitted, these condensed unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto as of and for the year ended December 31, 2016 contained in the Company’s 2016 Annual Report on Form 10-K (the “2016 Form 10-K”). In management’s opinion, all normal and recurring adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented have been included. Certain prior year amounts have been reclassified to conform to the current period presentation. Interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. The Company believes that the disclosures made in these condensed unaudited consolidated financial statements are adequate to make the information not misleading.
Reclassifications	Certain prior year amounts have been reclassified to conform to the current period presentation.
Principles of Consolidation	Principles of Consolidation The accompanying condensed unaudited consolidated financial statements include MasTec, Inc. and its subsidiaries and include the accounts of all majority owned subsidiaries over which the Company exercises control and, when applicable, entities in which the Company has a controlling financial interest. All significant intercompany balances and transactions have been eliminated in consolidation. Other parties’ interests in entities that MasTec consolidates are reported as non-controlling interests within equity. Net income or loss attributable to non-controlling interests is reported as a separate line item below net income or loss. The Company’s investments in entities for which the Company does not have a controlling interest, but for which it has the ability to exert significant influence, are accounted for using the equity method of accounting. Equity method investments are recorded as other long-term assets, or, for investments in a net liability position, within other long-term liabilities. Income or loss from these investments is recorded as a separate line item in the statements of operations. Intercompany profits or losses associated with the Company’s equity method investments are eliminated until realized by the investee in transactions with third parties. For equity investees in which the Company has an undivided interest in the assets, liabilities and profits or losses of an unincorporated entity, but the Company does not exercise control over the entity, the Company consolidates its proportional interest in the accounts of the entity. The cost method is used for investments in entities for which the Company does not have the ability to exert significant influence. Management determines whether each business entity in which it has equity interests, debt, or other investments constitutes a variable interest entity (“VIE”) based on the nature and characteristics of such arrangements. If an investment arrangement is determined to be a VIE, then management determines if the Company is the VIE’s primary beneficiary by evaluating several factors, including the Company’s: (i) risks and responsibilities; (ii) ownership interests; (iii) decision making powers; and (iv) financial interests, among other factors. If management determines the Company is the primary beneficiary of a VIE, then it would be consolidated, and other parties’ interests in the VIE would be accounted for as non-controlling interests. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the primary activities of the VIE and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, which, in either case, could be significant to the VIE.
Equity Method Investments	The Company’s investments in entities for which the Company does not have a controlling interest, but for which it has the ability to exert significant influence, are accounted for using the equity method of accounting. Equity method investments are recorded as other long-term assets, or, for investments in a net liability position, within other long-term liabilities. Income or loss from these investments is recorded as a separate line item in the statements of operations. Intercompany profits or losses associated with the Company’s equity method investments are eliminated until realized by the investee in transactions with third parties.
Unincorporated Entities, Proportionate Consolidation	For equity investees in which the Company has an undivided interest in the assets, liabilities and profits or losses of an unincorporated entity, but the Company does not exercise control over the entity, the Company consolidates its proportional interest in the accounts of the entity.
Cost Method Investments	The cost method is used for investments in entities for which the Company does not have the ability to exert significant influence.
Variable Interest Entities	Management determines whether each business entity in which it has equity interests, debt, or other investments constitutes a variable interest entity (“VIE”) based on the nature and characteristics of such arrangements. If an investment arrangement is determined to be a VIE, then management determines if the Company is the VIE’s primary beneficiary by evaluating several factors, including the Company’s: (i) risks and responsibilities; (ii) ownership interests; (iii) decision making powers; and (iv) financial interests, among other factors. If management determines the Company is the primary beneficiary of a VIE, then it would be consolidated, and other parties’ interests in the VIE would be accounted for as non-controlling interests. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the primary activities of the VIE and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, which, in either case, could be significant to the VIE.
Translation of Foreign Currencies	Translation of Foreign Currencies The assets and liabilities of foreign subsidiaries with a functional currency other than the U.S. dollar are translated into U.S. dollars at period-end exchange rates, with resulting translation gains or losses accumulated within other comprehensive income or loss. Revenue and expenses are translated into U.S. dollars at average rates of exchange during the applicable period. Substantially all of the Company’s foreign operations use their local currency as their functional currency. Currency gains or losses resulting from transactions executed in currencies other than the functional currency are included in other income or expense, net.
Management Estimates	Management Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires the use of estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Key estimates include: the recognition of revenue and project profit or loss (which the Company defines as project revenue, less project costs of revenue, including project-related depreciation), in particular, on construction contracts accounted for under the percentage-of-completion method, for which the recorded amounts require estimates of costs to complete and the amount of probable contract price adjustments; allowances for doubtful accounts; estimated fair values of goodwill and intangible assets; acquisition-related contingent consideration and investments in equity investees; asset lives used in computing depreciation and amortization; accrued self-insured claims; share-based compensation; other accruals and allowances; accounting for income taxes; and the estimated impact of litigation and other contingencies. While management believes that such estimates are reasonable when considered in conjunction with the Company’s consolidated financial position and results of operations taken as a whole, actual results could differ materially from those estimates.
Revenue Recognition	Revenue Recognition Revenue is derived from construction projects performed under master and other service agreements as well as from contracts for specific projects or jobs requiring the construction and installation of an entire infrastructure system or specified units within an entire infrastructure system. The Company frequently provides services under unit price or fixed price master service or other service agreements. Revenue and related costs for master and other service agreements billed on a time and materials basis are recognized as the services are rendered. Revenue derived from projects performed under master service and other service agreements totaled 31% and 45% of consolidated revenue for the three month periods ended June 30, 2017 and 2016, respectively, and totaled 37% and 47% for the six month periods ended June 30, 2017 and 2016, respectively. The Company also performs services under master and other service agreements on a fixed fee basis, under which MasTec furnishes specified units of service for a fixed price per unit of service and revenue is recognized as the services are rendered. Revenue from fixed price contracts provides for a fixed amount of revenue for the entire project, subject to certain additions for changed scope or specifications. Revenue from these contracts, as well as for certain projects pursuant to master and other service agreements, is recognized using the percentage-of-completion method, under which the percentage of revenue to be recognized for a given project is measured by the percentage of costs incurred to date on the contract to the total estimated costs for the contract. Such contracts provide that the customer accept completion of progress to date and compensate the Company for services rendered, which may be measured in terms of costs incurred, units installed, hours expended or some other measure of progress. Contract costs include all direct materials, labor and subcontracted costs and those indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and the operational costs of capital equipment. Much of the materials associated with the Company’s work are customer-furnished and are therefore not included in contract revenue and costs. The estimation process for revenue recognized under the percentage-of-completion method is based on the professional knowledge and experience of the Company’s project managers, engineers and financial professionals. Management reviews estimates of contract revenue and costs on an ongoing basis. Changes in job performance, job conditions and management’s assessment of expected contract settlements are factors that influence estimates of total contract value and total costs to complete those contracts and, therefore, the Company’s profit recognition. Changes in these factors may result in revisions to costs and income and their effects are recognized in the period in which the revisions are determined, which could materially affect the Company’s results of operations in the period in which such changes are recognized. For both the six month periods ended June 30, 2017 and 2016, project profit was affected by less than 5% as a result of changes in contract estimates included in projects that were in process as of December 31, 2016 and 2015. Provisions for losses on uncompleted contracts are made in the period in which such losses are determined to be probable and the amount can be reasonably estimated. The majority of fixed price contracts are completed within one year. The Company may incur costs subject to change orders, whether approved or unapproved by the customer, and/or claims related to certain contracts. Management determines the probability that such costs will be recovered based upon engineering studies and legal opinions, past practices with the customer, specific discussions, correspondence or preliminary negotiations with the customer. The Company treats such costs as a cost of contract performance in the period incurred if it is not probable that the costs will be recovered, and defers costs or recognizes revenue up to the amount of the related cost if it is probable that the contract price will be adjusted and can be reliably estimated. As of June 30, 2017 and December 31, 2016, the Company had approximately $19 million and $17 million, respectively, of change orders and/or claims that had been included as contract price adjustments on certain contracts that were in the process of being resolved in the normal course of business, including through negotiation, arbitration and other proceedings. These contract price adjustments, which are included within costs and earnings in excess of billings or billed accounts receivable, as appropriate, represent management’s best estimate of contract revenue that has been earned and that management believes is probable of collection. As of both June 30, 2017 and December 31, 2016, these change orders were primarily related to contracts in the Oil and Gas segment. The Company actively engages in substantive meetings with its customers to complete the final approval process, and generally expects these processes to be completed within one year. The amounts ultimately realized upon final acceptance by its customers could be higher or lower than such estimated amounts. Billings In Excess of Costs and Earnings (“BIEC”) on uncompleted contracts is classified within current liabilities. Costs and Earnings In Excess of Billings (“CIEB”), which is also referred to as work in process, is classified within current assets. Work in process on contracts is based on work performed but not yet billed to customers as per individual contract terms.
Revenue Recognition, Percentage-of-Completion Method	Revenue from fixed price contracts provides for a fixed amount of revenue for the entire project, subject to certain additions for changed scope or specifications. Revenue from these contracts, as well as for certain projects pursuant to master and other service agreements, is recognized using the percentage-of-completion method, under which the percentage of revenue to be recognized for a given project is measured by the percentage of costs incurred to date on the contract to the total estimated costs for the contract. Such contracts provide that the customer accept completion of progress to date and compensate the Company for services rendered, which may be measured in terms of costs incurred, units installed, hours expended or some other measure of progress. Contract costs include all direct materials, labor and subcontracted costs and those indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and the operational costs of capital equipment. Much of the materials associated with the Company’s work are customer-furnished and are therefore not included in contract revenue and costs. The estimation process for revenue recognized under the percentage-of-completion method is based on the professional knowledge and experience of the Company’s project managers, engineers and financial professionals. Management reviews estimates of contract revenue and costs on an ongoing basis. Changes in job performance, job conditions and management’s assessment of expected contract settlements are factors that influence estimates of total contract value and total costs to complete those contracts and, therefore, the Company’s profit recognition. Changes in these factors may result in revisions to costs and income and their effects are recognized in the period in which the revisions are determined, which could materially affect the Company’s results of operations in the period in which such changes are recognized. For both the six month periods ended June 30, 2017 and 2016, project profit was affected by less than 5% as a result of changes in contract estimates included in projects that were in process as of December 31, 2016 and 2015. Provisions for losses on uncompleted contracts are made in the period in which such losses are determined to be probable and the amount can be reasonably estimated. The majority of fixed price contracts are completed within one year.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements There have been no changes in the expected dates of adoption or estimated effects on the Company’s consolidated financial statements of recently issued accounting pronouncements from those disclosed in the Company’s 2016 Form 10-K. See below for additional discussion of recently issued accounting pronouncements. Accounting Pronouncements Not Yet Adopted In May 2017, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”). ASU 2017-09 clarifies when a change to the terms or conditions of a share-based payment award must be accounted for as modifications. Limited and administrative modifications that do not change the value, vesting conditions, or classification of the award are exempt from following the modification guidance in Topic 718. ASU 2017-09 is effective on a prospective basis for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The Company does not expect the adoption of this ASU to have a material effect on its consolidated financial statements. In February 2017, the FASB issued ASU 2017-05, Other Income- Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets (“ASU 2017-05”). ASU 2017-05 clarifies certain guidance under Subtopic 610-20 that was issued as part of the new revenue standard, including the recognition of gains and losses on the sale or transfer of nonfinancial assets to noncustomers, and clarifies accounting for contributions of nonfinancial assets to joint ventures, among other requirements. ASU 2017-05 is effective on a retrospective basis for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. The Company is currently evaluating the potential effect of this ASU on its consolidated financial statements. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”). The core principle of this ASU is that a company will recognize revenue when it transfers goods or services to customers in an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. In doing so, companies will need to use judgment and make estimates when evaluating contract terms and other relevant facts and circumstances. Additionally, ASU 2014-09 requires enhanced disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts. In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which delayed the effective date of ASU 2014-09 by one year. ASU 2014-09, as amended, is effective using either the full retrospective or modified retrospective transition approach for fiscal years, and for interim periods within those years, beginning after December 15, 2017. In 2016, the FASB issued several accounting standards updates to clarify certain topics within ASU 2014-09. The Company will adopt ASU 2014-09, and its related clarifying ASUs, as of January 1, 2018. The Company has substantially completed its assessment of the potential effects of these ASUs on its consolidated financial statements, business processes, systems and controls. The Company’s assessment included a detailed review of representative contracts at each of the Company’s business units and a comparison of its historical accounting policies and practices to the new standard. Based on the Company’s review of various types of revenue arrangements, the Company expects to recognize revenue and earnings over time utilizing the cost-to-cost measure of progress for its fixed price contracts and certain master service and other service agreements, consistent with current practice. For these contracts, the cost-to-cost measure of progress best depicts the transfer of control of goods or services to the customer under the new standard. Under the new standard and consistent with the Company’s current practice, the cost of uninstalled materials will generally be excluded from the measure of progress, unless specifically produced or fabricated for a project, because such cost does not appropriately depict the Company’s performance in transferring control of goods or services to the customer. The Company has substantially completed its analysis of the information necessary to enable the preparation of the financial statements and related disclosures under the new standard. As part of this analysis, the Company evaluated its information technology capabilities and systems, and does not expect to incur significant information technology costs to modify systems currently in place. The Company will implement targeted changes to its internal reporting processes to facilitate gathering the data needed for the new disclosure requirements. The Company will also implement updates to its control processes and procedures, as necessary, based on changes resulting from the new standard. The Company does not expect any such updates to materially affect the Company’s internal controls over financial reporting. The Company anticipates adopting the standard using the modified retrospective transition approach. Under this approach, the new standard would apply to all new contracts initiated on or after January 1, 2018. For existing contracts that have remaining obligations as of January 1, 2018, any difference between the recognition criteria in these ASUs and the Company’s current revenue recognition practices would be recognized using a cumulative effect adjustment to the opening balance of retained earnings. Any potential effect of adoption of these ASUs has not yet been quantified; however, based on the review of contracts across all of the Company’s business units to date, the adoption of these ASUs is not expected to have a material effect on the timing or amount of revenue recognized as compared to current practices. The Company expects to begin training its business units for the implementation of the new standard, and to continue developing the disclosures required by the new standard during the third quarter of 2017. Accounting Pronouncements Adopted as of January 1, 2017 The Company adopted ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (“ASU 2016-09”) effective January 1, 2017. Under ASU 2016-09, excess tax benefits (“windfalls”) or tax deficiencies (“shortfalls”) are recognized in the income statement, rather than as additional paid-in-capital as under the previous guidance, and are presented as operating cash flows, rather than as a financing activity. This ASU also increased the amount of tax that can be withheld by an employer for employee tax withholdings without resulting in liability classification of an award. Payments to taxing authorities for such employee withholdings are presented as financing activities. ASU 2016-09 also allows companies to account for forfeitures of share-based payments as they occur or to estimate such amounts. The provisions of ASU 2016-09 that were applicable to the Company were adopted on a prospective basis; the retrospective requirement to classify payments to taxing authorities for employee withholdings as a financing activity was consistent with the Company’s existing methodology, therefore did not result in a change. The adoption of ASU 2016-09 is expected to result in volatility in income tax expense given that windfalls or shortfalls are recognized in income tax expense in the periods in which they occur. The other components of this ASU did not have a material effect on the consolidated financial statements.

Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2017

Earnings Per Share [Abstract]

Schedule of Earnings Per Share Information

The following table provides details underlying the Company’s earnings per share calculations for the periods indicated (in thousands):



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2017		2016		2017		2016
Net income attributable to MasTec:
Net income - basic and diluted ^(a)	$	81,668	$	24,088	$	122,638	$	21,395
Weighted average shares outstanding:
Weighted average shares outstanding - basic	80,925		80,351		80,812		80,253
Dilutive common stock equivalents	1,367		915		1,414		790
Weighted average shares outstanding - diluted	82,292		81,266		82,226		81,043

Additional information:
Weighted average anti-dilutive common stock equivalents ^(b)	13		—		6		3


(a)	Calculated as total net income less amounts attributable to non-controlling interests.


(b)	Represents anti-dilutive common stock equivalents as calculated under the treasury stock method.

Goodwill and Other Intangible Assets (Tables)

6 Months Ended

Jun. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Goodwill by Segment

The following table provides details of goodwill by reportable segment as of June 30, 2017 (in millions):



	Communications		Oil and Gas			Electrical Transmission		Power Generation and Industrial		Total Goodwill
Goodwill, gross	$	463.1	$	382.2		$	149.9	$	117.6	$	1,112.8
Accumulated impairment losses	—		(72.5		)	—		—		(72.5		)
Goodwill, net	$	463.1	$	309.7		$	149.9	$	117.6	$	1,040.3

Rollforward of Other Intangible Assets

The following table provides a reconciliation of changes in other intangible assets for the period indicated (in millions):



	Other Intangible Assets
	Non-Amortizing				Amortizing
	Trade Names		Pre-Qualifications		Customer Relationships and Backlog			Other ^(a)			Total
Other intangible assets, gross, as of December 31, 2016	$	34.5	$	74.6	$	195.1		$	19.1		$	323.3
Accumulated amortization					(131.9		)	(11.7		)	(143.6		)
Other intangible assets, net, as of December 31, 2016	$	34.5	$	74.6	$	63.2		$	7.4		$	179.7
Additions from new business combinations	—		—		12.8			0.6			13.4
Amortization expense					(8.4		)	(0.6		)	(9.0		)
Currency translation adjustments	—		1.6		0.3			(0.1		)	1.8
Other intangible assets, net, as of June 30, 2017	$	34.5	$	76.2	$	67.9		$	7.3		$	185.9


(a)	Consists principally of trade names and non-compete agreements.

Accounts Receivable, Net of Allowance (Tables)

6 Months Ended

Jun. 30, 2017

Accounts Receivable [Member]

Schedule of Accounts Receivable, Net of Allowance [Line Items]

Schedule of Accounts Receivable, Net of Allowance

The following table provides details of accounts receivable, net of allowance, as of the dates indicated (in millions):



	June 30, 2017			December 31, 2016
Contract billings	$	784.5		$	564.2
Retainage	228.6			268.6
Costs and earnings in excess of billings	565.1			331.6
Accounts receivable, gross	$	1,578.2		$	1,164.4
Less allowance for doubtful accounts	(8.8		)	(8.4		)
Accounts receivable, net	$	1,569.4		$	1,156.0

Property and Equipment, Net (Tables)

6 Months Ended

Jun. 30, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment, Net

The following table provides details of property and equipment, net, including property and equipment held under capital leases as of the dates indicated (in millions):



	June 30, 2017			December 31, 2016
Land	$	4.6		$	4.6
Buildings and leasehold improvements	26.2			24.2
Machinery and equipment	1,155.6			997.8
Office furniture and equipment	148.9			146.1
Construction in progress	12.3			9.5
Total property and equipment	$	1,347.6		$	1,182.2
Less accumulated depreciation and amortization	(699.1		)	(633.1		)
Property and equipment, net	$	648.5		$	549.1

Debt (Tables)

6 Months Ended

Jun. 30, 2017

Debt Disclosure [Abstract]

Schedule of Carrying Values of Debt

The following table provides details of the carrying values of debt as of the dates indicated (in millions):



Description	Maturity Date	June 30, 2017			December 31, 2016
Senior secured credit facility:	February 22, 2022
Revolving loans		$	564.6		$	279.9
Term loan		250.0			237.5
4.875% Senior Notes	March 15, 2023	400.0			400.0
Capital lease obligations, weighted average interest rate of 3.3%	In installments through June 30, 2022	177.9			98.6
Notes payable and other debt obligations	Varies	11.2			19.8
Total long-term debt obligations		$	1,403.7		$	1,035.8
Less unamortized deferred financing costs		(14.4		)	(9.8		)
Total debt, net of deferred financing costs		$	1,389.3		$	1,026.0
Current portion of long-term debt		75.4			64.6
Long-term debt		$	1,313.9		$	961.4

Schedule of Activity, Restricted Shares

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21521-112644

+ Details

Stock-Based Compensation and Other Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2017

Share-based Compensation [Abstract]



Activity, restricted shares: ^(a)	Restricted Shares		Per Share Weighted Average Grant Date Fair Value
Non-vested restricted shares, as of December 31, 2016	1,970,586		$	21.61
Granted	188,843		39.44
Vested	(300,633	)	40.73
Canceled/forfeited	(17,400	)	16.57
Non-vested restricted shares, as of June 30, 2017	1,841,396		$	20.36


(a)	Includes 39,050 and 43,300 restricted stock units as of June 30, 2017 and December 31, 2016, respectively.

Schedule of Activity, Employee Stock Purchase Plans

The following table provides details pertaining to the Company’s ESPPs for the periods indicated:



	For the Six Months Ended June 30,
	2017		2016
Cash proceeds (in millions)	$	1.6	$	1.3
Common shares issued	49,502		83,680
Weighted average price per share	$	33.30	$	15.95
Weighted average per share grant date fair value	$	8.67	$	4.36

Schedule of Non-Cash Stock-Based Compensation Expense and Related Tax Effects

Details of non-cash stock-based compensation expense and related tax effects for the periods indicated were as follows (in millions):



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2017		2016		2017		2016
Non-cash stock-based compensation expense	$	3.4	$	3.9	$	7.2	$	7.4
Income Tax Effects:
Income tax effect of non-cash stock-based compensation	$	1.3	$	2.3	$	2.5	$	3.9
Excess tax benefit from non-cash stock-based compensation ^(a)	$	0.0	$	0.9	$	0.1	$	1.1

(a)

Other Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2017

Multiemployer Plans [Abstract]

Schedule of Covered Employees and Contributions, Multiemployer Plans

Total contributions to multiemployer plans, and the related number of employees covered by these plans, including with respect to the Company’s Canadian operations, for the periods indicated were as follows:



	Multiemployer Plans
	Covered Employees		Contributions (in millions)
	Low	High	Pension		Other Multiemployer		Total
For the Three Months Ended June 30:
2017	3,669	7,057	$	28.3	$	2.7	$	31.0
2016	1,410	4,170	$	12.2	$	2.5	$	14.7
For the Six Months Ended June 30:
2017	550	7,057	$	32.0	$	5.3	$	37.3
2016	1,112	4,170	$	17.0	$	4.7	$	21.7

Segments and Related Information (Tables)

6 Months Ended

Jun. 30, 2017

Segment Reporting [Abstract]

Schedule of Financial Information by Reportable Segment

Summarized financial information for MasTec’s reportable segments is presented and reconciled to consolidated financial information for total MasTec in the following tables (in millions):



	For the Three Months Ended June 30,						For the Six Months Ended June 30,
Revenue:	2017			2016			2017			2016
Communications ^(a)	$	592.2		$	592.2		$	1,151.7		$	1,103.8
Oil and Gas	1,140.4			425.6			1,596.2			718.4
Electrical Transmission	96.6			95.6			195.4			181.9
Power Generation and Industrial	60.7			119.7			107.3			201.1
Other	1.9			3.9			3.6			7.3
Eliminations	(1.6		)	(4.6		)	(5.8		)	(5.9		)
Consolidated revenue	$	1,890.2		$	1,232.4		$	3,048.4		$	2,206.6


(a)	Revenue generated primarily by utilities customers represented 11.5% and 11.0% of Communications segment revenue for the three month periods ended June 30, 2017 and 2016, respectively, and represented 12.4% and 10.7% for the six month periods ended June 30, 2017 and 2016, respectively.



	For the Three Months Ended June 30,						For the Six Months Ended June 30,
EBITDA:	2017			2016			2017			2016
Communications	$	59.5		$	66.4		$	107.8		$	128.1
Oil and Gas	154.0			53.6			247.9			69.8
Electrical Transmission	3.5			(9.9		)	6.7			(33.7		)
Power Generation and Industrial	4.7			4.8			5.6			7.7
Other	6.8			0.3			1.5			0.5
Corporate	(29.6		)	(19.9		)	(47.1		)	(30.9		)
Consolidated EBITDA	$	198.9		$	95.3		$	322.4		$	141.5



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
Depreciation and Amortization:	2017		2016		2017		2016
Communications	$	13.5	$	12.4	$	25.5	$	24.6
Oil and Gas	23.2		19.3		45.1		37.5
Electrical Transmission	5.7		5.8		11.4		11.0
Power Generation and Industrial	1.4		1.5		2.9		3.1
Other	0.0		0.0		0.1		0.0
Corporate	1.6		1.7		3.3		3.5
Consolidated depreciation and amortization	$	45.4	$	40.7	$	88.3	$	79.7

Reconciliation of Consolidated Income before Income Taxes to EBITDA

The following table, which may contain slight summation differences due to rounding, presents a reconciliation of consolidated income before income taxes to EBITDA (in millions):



	For the Three Months Ended June 30,				For the Six Months Ended June 30,
EBITDA Reconciliation:	2017		2016		2017		2016
Income before income taxes	$	138.8	$	42.0	$	206.8	$	37.1
Plus:
Interest expense, net	14.8		12.6		27.4		24.8
Depreciation and amortization	45.4		40.7		88.3		79.7
Consolidated EBITDA	$	198.9	$	95.3	$	322.4	$	141.5

Schedule of Significant Customers, Revenue Concentration Information

Revenue concentration information for significant customers as a percentage of total consolidated revenue was as follows:



	For the Three Months Ended June 30,		For the Six Months Ended June 30,
Customer:	2017	2016	2017	2016
Energy Transfer affiliates ^(a)	47%	22%	35%	20%
AT&T (including DIRECTV^®) ^(b)	22%	36%	27%	37%


(a)	The Company's relationship with Energy Transfer affiliates is based upon various construction contracts for pipeline activities with Energy Transfer Partners L.P., and their subsidiaries and affiliates, all of which are consolidated by Energy Transfer Equity, L.P. Revenue from Energy Transfer affiliates is included in the Oil and Gas segment.

(b)

Supplemental Guarantor Financial Information (Tables)

6 Months Ended

Jun. 30, 2017

Condensed Unaudited Financial Statements, Supplemental Guarantor Information [Abstract]

Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss)

CONDENSED UNAUDITED CONSOLIDATING STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (in millions)



For the Three Months Ended June 30, 2017	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	1,818.1		$	122.9		$	(50.8	)	$	1,890.2
Costs of revenue, excluding depreciation and amortization	—			1,566.3			110.8			(50.8		)	1,626.3
Depreciation and amortization	—			37.1			8.3			—			45.4
General and administrative expenses	0.6			66.5			3.7			—			70.8
Interest expense (income), net	—			30.4			(15.6		)	—			14.8
Equity in earnings of unconsolidated affiliates	—			—			(6.1		)	—			(6.1		)
Other (income) expense, net	—			(5.3		)	5.4			—			0.1
(Loss) income before income taxes	$	(0.6	)	$	123.1		$	16.3		$	—		$	138.8
Benefit from (provision for) income taxes	0.2			(44.7		)	(10.9		)	—			(55.4		)
Net (loss) income before equity in income from subsidiaries	$	(0.4	)	$	78.4		$	5.4		$	—		$	83.3
Equity in income from subsidiaries, net of tax	82.1			—			—			(82.1		)	—
Net income (loss)	$	81.7		$	78.4		$	5.4		$	(82.1	)	$	83.3
Net income attributable to non-controlling interests	—			—			1.7			—			1.7
Net income (loss) attributable to MasTec, Inc.	$	81.7		$	78.4		$	3.7		$	(82.1	)	$	81.7
Comprehensive income (loss)	$	79.5		$	78.4		$	3.2		$	(79.9	)	$	81.2



For the Three Months Ended June 30, 2016	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	1,149.4		$	93.5		$	(10.5	)	$	1,232.4
Costs of revenue, excluding depreciation and amortization	—			995.0			83.7			(10.5		)	1,068.2
Depreciation and amortization	—			31.7			9.0			—			40.7
General and administrative expenses	0.6			61.5			5.8			—			67.9
Interest expense (income), net	—			27.8			(15.2		)	—			12.6
Equity in earnings of unconsolidated affiliates	—			—			(0.5		)	—			(0.5		)
Other expense (income), net	—			1.8			(0.3		)	—			1.5
(Loss) income before income taxes	$	(0.6	)	$	31.6		$	11.0		$	—		$	42.0
Benefit from (provision for) income taxes	0.2			(12.6		)	(5.2		)	—			(17.6		)
Net (loss) income before equity in income from subsidiaries	$	(0.4	)	$	19.0		$	5.8		$	—		$	24.4
Equity in income from subsidiaries, net of tax	24.4			—			—			(24.4		)	—
Net income (loss)	$	24.0		$	19.0		$	5.8		$	(24.4	)	$	24.4
Net income attributable to non-controlling interests	—			—			0.4			—			0.4
Net income (loss) attributable to MasTec, Inc.	$	24.0		$	19.0		$	5.4		$	(24.4	)	$	24.1
Comprehensive income (loss)	$	19.8		$	19.0		$	1.4		$	(20.1	)	$	20.1

CONDENSED UNAUDITED CONSOLIDATING STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (in millions)



For the Six Months Ended June 30, 2017	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	2,903.2		$	217.0		$	(71.8	)	$	3,048.4
Costs of revenue, excluding depreciation and amortization	—			2,457.4			211.9			(71.8		)	2,597.5
Depreciation and amortization	—			71.1			17.2			—			88.3
General and administrative expenses	1.2			126.0			8.4			—			135.6
Interest expense (income), net	—			58.3			(30.9		)	—			27.4
Equity in earnings of unconsolidated affiliates	—			—			(7.7		)	—			(7.7		)
Other (income) expense , net	—			(5.3		)	5.9			—			0.6
(Loss) income before income taxes	$	(1.2	)	$	195.7		$	12.3		$	—		$	206.8
Benefit from (provision for) income taxes	0.4			(71.3		)	(11.9		)	—			(82.8		)
Net (loss) income before equity in income from subsidiaries	$	(0.8	)	$	124.4		$	0.4		$	—		$	124.0
Equity in income from subsidiaries, net of tax	123.4			—			—			(123.4		)	—
Net income (loss)	$	122.6		$	124.4		$	0.4		$	(123.4	)	$	124.0
Net income attributable to non-controlling interests	—			—			1.3			—			1.3
Net income (loss) attributable to MasTec, Inc.	$	122.6		$	124.4		$	(1.0	)	$	(123.4	)	$	122.6
Comprehensive income (loss)	$	122.3		$	124.4		$	—		$	(123.1	)	$	123.6



For the Six Months Ended June 30, 2016	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations			Consolidated MasTec, Inc.
Revenue	$	—		$	2,027.7		$	189.5		$	(10.6	)	$	2,206.6
Costs of revenue, excluding depreciation and amortization	—			1,772.3			190.9			(10.6		)	1,952.6
Depreciation and amortization	—			63.0			16.7			—			79.7
General and administrative expenses	1.2			111.5			15.2			—			127.9
Interest expense (income), net	—			55.2			(30.4		)	—			24.8
Equity in earnings of unconsolidated affiliates	—			—			(3.6		)	—			(3.6		)
Other income, net	—			(9.4		)	(2.4		)	—			(11.8		)
(Loss) income before income taxes	$	(1.2	)	$	35.1		$	3.1		$	—		$	37.1
Benefit from (provision for) income taxes	0.5			(14.0		)	(2.0		)	—			(15.5		)
Net (loss) income before equity in income from subsidiaries	$	(0.7	)	$	21.1		$	1.1		$	—		$	21.6
Equity in income from subsidiaries, net of tax	22.1			—			—			(22.1		)	—
Net income (loss)	$	21.4		$	21.1		$	1.1		$	(22.1	)	$	21.6
Net income attributable to non-controlling interests	—			—			0.2			—			0.2
Net income (loss) attributable to MasTec, Inc.	$	21.4		$	21.1		$	0.9		$	(22.1	)	$	21.4
Comprehensive income (loss)	$	14.7		$	21.1		$	(5.6	)	$	(15.4	)	$	14.8

Condensed Unaudited Consolidating Balance Sheets

CONDENSED UNAUDITED CONSOLIDATING BALANCE SHEETS (in millions)



As of June 30, 2017	MasTec, Inc.		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Eliminations			Consolidated MasTec, Inc.
Assets
Total current assets	$	—	$	1,649.5	$	212.8	$	(71.6	)	$	1,790.7
Property and equipment, net	—		556.1		92.4		—			648.5
Goodwill and other intangible assets, net	—		1,086.4		139.8		—			1,226.2
Investments in and advances to consolidated affiliates, net	1,212.9		806.2		749.0		(2,768.1		)	—
Other long-term assets	13.1		23.0		122.0		—			158.1
Total assets	$	1,226.0	$	4,121.2	$	1,316.0	$	(2,839.7	)	$	3,823.5
Liabilities and equity
Total current liabilities	$	—	$	902.4	$	97.9	$	(71.6	)	$	928.7
Long-term debt	—		1,299.5		14.4		—			1,313.9
Other long-term liabilities	—		335.6		12.1		—			347.7
Total liabilities	$	—	$	2,537.5	$	124.4	$	(71.6	)	$	2,590.3
Total equity	$	1,226.0	$	1,583.7	$	1,191.6	$	(2,768.1	)	$	1,233.2
Total liabilities and equity	$	1,226.0	$	4,121.2	$	1,316.0	$	(2,839.7	)	$	3,823.5



As of December 31, 2016	MasTec, Inc.		Guarantor Subsidiaries		Non-Guarantor Subsidiaries		Eliminations			Consolidated MasTec, Inc.
Assets
Total current assets	$	—	$	1,256.3	$	175.8	$	(29.6	)	$	1,402.5
Property and equipment, net	—		456.6		92.5		—			549.1
Goodwill and other intangible assets, net	—		1,037.4		138.2		—			1,175.6
Investments in and advances to consolidated affiliates, net	1,083.9		625.9		861.2		(2,571.0		)	—
Other long-term assets	12.6		25.3		18.0		—			55.9
Total assets	$	1,096.5	$	3,401.5	$	1,285.7	$	(2,600.6	)	$	3,183.1
Liabilities and equity
Total current liabilities	$	—	$	759.7	$	109.9	$	(29.6	)	$	840.0
Long-term debt	—		938.7		22.7		—			961.4
Other long-term liabilities	—		256.2		21.9		—			278.1
Total liabilities	$	—	$	1,954.6	$	154.5	$	(29.6	)	$	2,079.5
Total equity	$	1,096.5	$	1,446.9	$	1,131.2	$	(2,571.0	)	$	1,103.6
Total liabilities and equity	$	1,096.5	$	3,401.5	$	1,285.7	$	(2,600.6	)	$	3,183.1

Condensed Unaudited Consolidating Statements of Cash Flows

CONDENSED UNAUDITED CONSOLIDATING STATEMENTS OF CASH FLOWS (in millions)



For the Six Months Ended June 30, 2017	MasTec, Inc.		Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations		Consolidated MasTec, Inc.
Net cash (used in) operating activities	$	—	$	(52.9	)	$	(35.1	)	$	—	$	(88.0	)
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	—		(37.4		)	—			—		(37.4		)
Capital expenditures	—		(46.8		)	(10.1		)	—		(56.9		)
Proceeds from sale of property and equipment	—		6.8			0.6			—		7.4
Payments for other investments	—		(1.2		)	(73.3		)	—		(74.5		)
Proceeds from other investments	—		—			12.1			—		12.1
Net cash used in investing activities	$	—	$	(78.6	)	$	(70.7	)	$	—	$	(149.3	)
Cash flows from financing activities:
Proceeds from credit facilities	—		1,141.2			12.0			—		1,153.2
Repayments of credit facilities	—		(850.2		)	(18.9		)	—		(869.1		)
Repayments of other borrowings and capital lease obligations	—		(35.8		)	(5.3		)	—		(41.1		)
Payments of acquisition-related contingent consideration	—		(18.8		)	—			—		(18.8		)
Distributions to non-controlling interests	—		—			(1.3		)	—		(1.3		)
Proceeds from stock-based awards, net	0.0		0.0			0.0			—		0.0
Other financing activities, net	—		(6.2		)	—			—		(6.2		)
Net financing activities and advances (to) from consolidated affiliates	—		(115.5		)	115.5			—		—
Net cash provided by financing activities	$	—	$	114.7		$	101.9		$	—	$	216.6
Effect of currency translation on cash	—		—			0.1			—		0.1
Net (decrease) increase in cash and cash equivalents	$	—	$	(16.8	)	$	(3.7	)	$	—	$	(20.5	)
Cash and cash equivalents - beginning of period	$	—	$	28.3		$	10.5		$	—	$	38.8
Cash and cash equivalents - end of period	$	—	$	11.4		$	6.8		$	—	$	18.2



For the Six Months Ended June 30, 2016	MasTec, Inc.			Guarantor Subsidiaries			Non-Guarantor Subsidiaries			Eliminations		Consolidated MasTec, Inc.
Net cash (used in) provided by operating activities	$	—		$	(30.2	)	$	58.7		$	—	$	28.5
Cash flows from investing activities:
Cash paid for acquisitions, net of cash acquired	—			(4.1		)	—			—		(4.1		)
Capital expenditures	—			(61.3		)	(2.6		)	—		(63.9		)
Proceeds from sale of property and equipment	—			9.1			1.0			—		10.1
Payments for other investments	—			(1.2		)	(1.5		)	—		(2.7		)
Proceeds from other investments	—			0.7			—			—		0.7
Net cash used in investing activities	$	—		$	(56.8	)	$	(3.1	)	$	—	$	(59.9	)
Cash flows from financing activities:
Proceeds from credit facilities	—			625.1			59.2			—		684.3
Repayments of credit facilities	—			(539.1		)	(65.5		)	—		(604.6		)
Repayments of other borrowings and capital lease obligations	—			(25.5		)	(8.0		)	—		(33.5		)
Payments of acquisition-related contingent consideration	—			(14.6		)	—			—		(14.6		)
Proceeds from (payments for) stock-based awards, net	3.3			(0.3		)	0.3			—		3.3
Other financing activities, net	—			1.1			—			—		1.1
Net financing activities and advances (to) from consolidated affiliates	(3.3		)	37.2			(33.9		)	—		—
Net cash provided by (used in) financing activities	$	—		$	83.9		$	(47.9	)	$	—	$	36.0
Effect of currency translation on cash	—			—			(0.9		)	—		(0.9		)
Net (decrease) increase in cash and cash equivalents	$	—		$	(3.1	)	$	6.8		$	—	$	3.7
Cash and cash equivalents - beginning of period	$	—		$	4.8		$	0.2		$	—	$	5.0
Cash and cash equivalents - end of period	$	—		$	1.7		$	7.0		$	—	$	8.7

Business, Basis of Presentation and Significant Accounting Policies (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016	Dec. 31, 2016 USD ($)
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Number of reportable segments \| segment			5
Revenue Recognition [Line Items]
Unapproved change orders, description			The Company may incur costs subject to change orders, whether approved or unapproved by the customer, and/or claims related to certain contracts. Management determines the probability that such costs will be recovered based upon engineering studies and legal opinions, past practices with the customer, specific discussions, correspondence or preliminary negotiations with the customer. The Company treats such costs as a cost of contract performance in the period incurred if it is not probable that the costs will be recovered, and defers costs or recognizes revenue up to the amount of the related cost if it is probable that the contract price will be adjusted and can be reliably estimated. As of June 30, 2017 and December 31, 2016, the Company had approximately $19 million and $17 million, respectively, of change orders and/or claims that had been included as contract price adjustments on certain contracts that were in the process of being resolved in the normal course of business, including through negotiation, arbitration and other proceedings. These contract price adjustments, which are included within costs and earnings in excess of billings or billed accounts receivable, as appropriate, represent management’s best estimate of contract revenue that has been earned and that management believes is probable of collection. As of both June 30, 2017 and December 31, 2016, these change orders were primarily related to contracts in the Oil and Gas segment. The Company actively engages in substantive meetings with its customers to complete the final approval process, and generally expects these processes to be completed within one year. The amounts ultimately realized upon final acceptance by its customers could be higher or lower than such estimated amounts.
Accounts Receivable [Member]
Revenue Recognition [Line Items]
Unapproved change orders, expected to be billed and collected within one year, amount (in dollars) \| $	$ 19		$ 19		$ 17
Maximum [Member]
Revenue Recognition [Line Items]
Fixed price contract, percentage-of-completion method, term within which generally completed (in years)			1 year
Change order approval process, term within which expected to be completed (in years)			1 year
Contracts Accounted for under Percentage-of-Completion [Member] \| Maximum [Member]
Revenue Recognition [Line Items]
Change in accounting estimate, percentage-of-completion projects, financial effect on project profit, percentage			5.00%	5.00%
Master Service and Other Service Agreements [Member] \| Concentration Risk from Type of Arrangement [Member] \| Revenue [Member]
Revenue Recognition [Line Items]
Concentration risk, percentage of total	31.00%	45.00%	37.00%	47.00%

Earnings Per Share (Narrative) (Details) - shares	3 Months Ended		6 Months Ended
Earnings Per Share (Narrative) (Details) - shares	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Earnings Per Share [Line Items]
Computation of earnings per share, methodology			Basic earnings or loss per share is computed by dividing net income or loss attributable to MasTec by the weighted average number of common shares outstanding for the period, which excludes non-participating unvested restricted share awards. Diluted earnings per share is computed by dividing net income attributable to MasTec by the weighted average number of fully diluted shares, as calculated under the treasury stock method, which includes the potential effect of dilutive common stock equivalents, such as issued but unvested restricted shares and/or outstanding but unexercised stock options. The Company has no remaining outstanding stock options; all options under the Company’s stock option grants were exercised in 2016. If the Company reports a loss, rather than income, the computation of diluted loss per share excludes the effect of dilutive common stock equivalents, as their effect would be anti-dilutive.
Dilutive common stock equivalents (in shares)	1,367,000	915,000	1,414,000	790,000
ASU 2016-09 [Member]
Earnings Per Share [Line Items]
Dilutive common stock equivalents (in shares)	300,000		300,000
Common Stock [Member]
Earnings Per Share [Line Items]
Remaining stock options (in shares)	0		0		0

Earnings Per Share (Schedule of Earnings Per Share Information) (Details) - USD ($)
shares in Thousands, $ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2017

Jun. 30, 2016

Jun. 30, 2017

Jun. 30, 2016

Net income attributable to MasTec:

Net income - basic (in dollars)

^[1]

$ 81,668

$ 24,088

$ 122,638

$ 21,395

Net income - diluted (in dollars)

^[1]

$ 81,668

$ 24,088

$ 122,638

$ 21,395

Weighted average shares outstanding:

Weighted average shares outstanding - basic

80,925

80,351

80,812

80,253

Dilutive common stock equivalents (in shares)

1,367

915

1,414

790

Weighted average shares outstanding - diluted

82,292

81,266

82,226

81,043

Common Stock [Member]

Weighted average shares outstanding:

Weighted average anti-dilutive common stock equivalents (in shares)

^[2]

[1]	Calculated as total net income less amounts attributable to non-controlling interests.
[2]	Represents anti-dilutive common stock equivalents as calculated under the treasury stock method.

Goodwill and Other Intangible Assets (Schedule of Goodwill by Segment) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, gross	$ 1,112,800
Accumulated impairment losses	(72,500)
Goodwill, net	1,040,302	$ 995,874
Communications [Member]
Goodwill [Line Items]
Goodwill, gross	463,100
Accumulated impairment losses	0
Goodwill, net	463,100
Oil and Gas [Member]
Goodwill [Line Items]
Goodwill, gross	382,200
Accumulated impairment losses	(72,500)
Goodwill, net	309,700
Electrical Transmission [Member]
Goodwill [Line Items]
Goodwill, gross	149,900
Accumulated impairment losses	0
Goodwill, net	149,900
Power Generation and Industrial [Member]
Goodwill [Line Items]
Goodwill, gross	117,600
Accumulated impairment losses	0
Goodwill, net	$ 117,600

Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Goodwill [Line Items]
Goodwill, additions from new business combinations			$ 42.4
Amortization expense, intangible assets	$ 4.9	$ 5.3	9.0	$ 10.5
Earn-Out Arrangements [Member]
Goodwill [Line Items]
Accruals of acquisition-related contingent consideration				5.8
Goodwill, Gross [Member]
Goodwill [Line Items]
Goodwill, currency translation gains (losses)			4.6	8.0
Goodwill, Accumulated Impairment Losses [Member]
Goodwill [Line Items]
Goodwill, currency translation gains (losses)			$ (2.6)	$ (4.2)

Goodwill and Other Intangible Assets (Rollforward of Other Intangible Assets) (Details) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2017

Jun. 30, 2016

Jun. 30, 2017

Jun. 30, 2016

Dec. 31, 2016

Other intangible assets, gross

$ 323,300

Accumulated amortization

(143,600)

Other intangible assets, net, beginning balance

$ 179,711

Additions from new business combinations, other intangible assets

13,400

Amortization expense

$ (4,900)

$ (5,300)

(9,000)

$ (10,500)

Currency translation adjustments, other intangible assets

1,800

Other intangible assets, net, ending balance

185,932

Customer Relationships and Backlog [Member]

Other intangible assets, amortizing, gross

195,100

Accumulated amortization

(131,900)

Other intangible assets, net, amortizing, beginning balance

63,200

Additions from new business combinations, amortizing intangible assets

12,800

Amortization expense

(8,400)

Currency translation adjustments, amortizing intangible assets

300

Other intangible assets, net, amortizing, ending balance

67,900

Other Amortizing Intangible Assets [Member]

Other intangible assets, amortizing, gross

^[1]

19,100

Accumulated amortization

^[1]

(11,700)

Other intangible assets, net, amortizing, beginning balance

^[1]

7,400

Additions from new business combinations, amortizing intangible assets

600

Amortization expense

^[1]

(600)

Currency translation adjustments, amortizing intangible assets

^[1]

(100)

Other intangible assets, net, amortizing, ending balance

^[1]

7,300

Trade Names [Member]

Other intangible assets, non-amortizing, carrying amount

34,500

Other intangible assets, non-amortizing, beginning balance

34,500

Additions from new business combinations, non-amortizing intangible assets

Currency translation adjustments, non-amortizing intangible assets

Other intangible assets, non-amortizing, ending balance

34,500

Pre-Qualifications [Member]

Other intangible assets, non-amortizing, carrying amount

76,200

74,600

$ 74,600

Other intangible assets, non-amortizing, beginning balance

74,600

Additions from new business combinations, non-amortizing intangible assets

Currency translation adjustments, non-amortizing intangible assets

1,600

Other intangible assets, non-amortizing, ending balance

$ 76,200

[1]	Consists principally of trade names and non-compete agreements.

Goodwill and Other Intangible Assets (2017 Acquisition) (Narrative) (Details) - April 2017 Acquisition [Member] - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Apr. 30, 2017	Jun. 30, 2017	Apr. 01, 2017
Business Combination [Line Items]
Business combinations, effective date		Apr. 01, 2017
Business combinations, description of acquired entity		a leading wireline/fiber deployment construction contractor with operations in several western states, predominantly servicing cable system operators
Business combinations, payments in cash (in dollars)	$ 38.2
Earn-Out Arrangements [Member]
Business Combination [Line Items]
Business combinations, contingent consideration, earn-out period (in years)		5 years
Business combinations, contingent consideration, fair value of earn-out (in dollars)			$ 25.0

Fair Value of Financial Instruments (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Narrative) (Details) - Earn-Out Arrangements [Member] - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Additions from new business combinations, ASC 805 contingent consideration	$ 25.0			$ 25.0
Payments of ASC 805 contingent consideration	18.8	$ 10.6		$ 18.8	$ 10.6
Other Income (Expense) [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Reduction (increase) in ASC 805 contingent consideration liability, gain (loss) included in earnings	8.6		$ 2.3
Foreign Currency Translation Adjustments [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Foreign currency translation gains (losses), included in other comprehensive income (loss), ASC 805 contingent consideration					$ (0.6)
Level 3 [Member] \| Fair Value Measurements, Recurring [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Fair value measurements, valuation techniques				The fair value of the Company’s ASC 805 contingent consideration is estimated using an income approach and incorporates significant inputs not observable in the market.
Level 3 [Member] \| Fair Value [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
ASC 805 contingent consideration, fair value	43.3			$ 43.3		$ 45.8
Level 3 [Member] \| Fair Value [Member] \| Fair Value Measurements, Recurring [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
Range of potential undiscounted earn-out liabilities, low	9.0			9.0
Range of potential undiscounted earn-out liabilities, high	69.0			69.0
Level 3 [Member] \| Fair Value [Member] \| Other Current Liabilities [Member]
Fair Value, Financial Instruments Measured on a Recurring Basis [Line Items]
ASC 805 contingent consideration, fair value	$ 19.1			$ 19.1		$ 21.8

Fair Value of Financial Instruments (Assets and Liabilities Measured at Fair Value on a Non-Recurring Basis) (Narrative) (Details) - 4.875% Senior Notes [Member] - Senior Notes [Member] - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Debt instrument, interest rate (percentage)	4.875%
Fair Value Measurements, Non-Recurring [Member] \| Level 1 [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Fair value measurements, valuation techniques	the estimated fair value of the Company’s 4.875% Senior Notes, based on quoted market prices in active markets, a Level 1 input
Fair Value Measurements, Non-Recurring [Member] \| Gross Carrying Amount [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
4.875% Senior Notes (in dollars)	$ 400.0	$ 400.0
Fair Value Measurements, Non-Recurring [Member] \| Fair Value [Member] \| Level 1 [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
4.875% Senior Notes (in dollars)	$ 398.0	$ 388.0

Fair Value of Financial Instruments (Cost and Equity Investees) (Narrative) (Details)	3 Months Ended				6 Months Ended
	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2014
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Undistributed earnings from equity method investees	$ 3,300,000				$ 3,300,000
Equity in earnings (losses) of unconsolidated affiliates	6,060,000		$ 489,000		7,706,000	$ 3,555,000
Unrealized losses on equity investee activity, net of tax	2,730,000		4,577,000		2,095,000	12,587,000
Credit Facility [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Letters of credit issued	$ 305,600,000				$ 305,600,000		$ 314,300,000
Equity Investees [Member] \| Pacer [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Construction projects, percentage complete	100.00%				100.00%
Investee [Member] \| Pacer [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Number of joint ventures								2
Investee [Member] \| Pacer [Member] \| Canadian Dollars [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity in earnings (losses) of unconsolidated affiliates				$ 3,600,000
Revenue, related parties				$ 600,000
Net investment, equity investees	$ 14,300,000				$ 14,300,000		31,400,000
Other equity investee, proceeds related to ongoing liquidation		$ 12,100,000
Expense, change in expected recovery from investee	(5,800,000)
Investee [Member] \| Pacer [Member] \| Canadian Dollars [Member] \| Equity Investees, Remaining Amounts Committed [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Contractual joint venture, additional amounts committed	0				0
CCI [Member] \| Immediate Family Member of Management or Principal Owner [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Cost method investment, original cost	$ 15,000,000				$ 15,000,000
Waha JVs [Member] \| Equity Investees [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Number of pipelines in operation	2				2
Equity investee, equity and other contributions	$ 19,900,000				$ 73,300,000
Revenue, related parties	100,200,000		51,600,000		251,600,000	61,900,000
Receivables, including retainage, net of BIEC, related parties	54,100,000				54,100,000		71,200,000
Net investment, equity investees	107,000,000				107,000,000		6,000,000
Waha JVs [Member] \| Equity Investees [Member] \| Interest Rate Swaps [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Unrealized losses on equity investee activity	4,400,000		7,500,000		3,400,000	20,500,000
Unrealized losses on equity investee activity, net of tax	2,700,000		4,600,000		2,100,000	$ 12,600,000
Waha JVs [Member] \| Equity Investees [Member] \| Other [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Equity in earnings (losses) of unconsolidated affiliates	6,100,000		$ 500,000		7,700,000
Waha JVs [Member] \| Equity Investees [Member] \| Credit Facility [Member] \| Financial Standby [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Letters of credit issued	$ 19,000,000				$ 19,000,000		$ 91,000,000
Joint Venture Liquidated in 2016 [Member] \| Investee [Member] \| Pacer [Member]
Fair Value, Financial Instruments Measured on a Non-Recurring Basis [Line Items]
Number of joint ventures							1

Accounts Receivable, Net of Allowance (Schedule of Accounts Receivable, Net of Allowance) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts Receivable, Net of Allowance
Contract billings	$ 784,500	$ 564,200
Retainage	228,600	268,600
Costs and earnings in excess of billings	565,100	331,600
Accounts receivable, gross	1,578,200	1,164,400
Less allowance for doubtful accounts	(8,800)	(8,400)
Accounts receivable, net	$ 1,569,392	$ 1,156,031

Accounts Receivable, Net of Allowance (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule of Accounts Receivable, Net of Allowance [Line Items]
Provisions for doubtful accounts	$ 0.2	$ 1.3	$ 0.7	$ 1.7
Interest Expense [Member] \| Financing Receivable [Member]
Schedule of Accounts Receivable, Net of Allowance [Line Items]
Non-recourse financing arrangement, discount charge	$ 1.7	$ 0.5	$ 2.6	$ 0.9

Property and Equipment, Net (Schedule of Property and Equipment, Net) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Property and Equipment [Line Items]
Property and equipment	$ 1,347,600	$ 1,182,200
Less accumulated depreciation and amortization	(699,100)	(633,100)
Property and equipment, net	648,456	549,084
Land [Member]
Property and Equipment [Line Items]
Property and equipment	4,600	4,600
Building and Leasehold Improvements [Member]
Property and Equipment [Line Items]
Property and equipment	26,200	24,200
Machinery and Equipment [Member]
Property and Equipment [Line Items]
Property and equipment	1,155,600	997,800
Office Furniture and Equipment [Member]
Property and Equipment [Line Items]
Property and equipment	148,900	146,100
Construction in Progress [Member]
Property and Equipment [Line Items]
Property and equipment	$ 12,300	$ 9,500

Property and Equipment, Net (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Property and Equipment [Line Items]
Capitalized internal-use software, gross	$ 108,900		$ 108,900		$ 107,800
Capitalized internal-use software, net	26,800		26,800		$ 30,900
Depreciation and amortization	45,379	$ 40,657	88,282	$ 79,664
Property and Equipment [Member]
Property and Equipment [Line Items]
Depreciation and amortization	$ 40,500	$ 35,400	$ 79,200	$ 69,100

Debt (Schedule of Carrying Values of Debt) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Capital lease obligations	$ 177,900	$ 98,600
Total long-term debt obligations	1,403,700	1,035,800
Less unamortized deferred financing costs	(14,400)	(9,800)
Total debt, net of deferred financing costs	1,389,300	1,026,000
Current portion of long-term debt	75,401	64,600
Long-term debt	$ 1,313,860	961,379
Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maturity date	Feb. 22, 2022
Credit Facility [Member] \| Revolving Loans [Member]
Debt Instrument [Line Items]
Long-term debt obligations	$ 564,600	279,900
Credit Facility [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Long-term debt obligations	$ 250,000	237,500
Senior Notes [Member] \| 4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Mar. 15, 2023
Long-term debt obligations	$ 400,000	400,000
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Capital lease obligations, expiration date, range, end	Jun. 30, 2022
Notes Payable and Other Debt Obligations [Member]
Debt Instrument [Line Items]
Long-term debt obligations	$ 11,200	$ 19,800

Debt (Schedule of Carrying Values of Debt) (Interest Rates) (Details)	Jun. 30, 2017
Senior Notes [Member] \| 4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate (percentage)	4.875%
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Debt instrument, weighted average interest rate (percentage)	3.30%

Debt (Senior Secured Credit Facility) (Narrative) (Details)			1 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jul. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Debt Instrument [Line Items]
Line of credit facility, term loan, proceeds received				$ 1,153,230,000	$ 684,287,000
Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,500,000,000	$ 1,200,000,000		$ 1,500,000,000
Line of credit facility, maturity date				Feb. 22, 2022
Line of credit facility, description of variable rate				Outstanding revolving loans and the term loan under the Credit Facility bear interest, at the Company’s option, at a rate equal to either (a) a Eurocurrency Rate, as defined in the 2017 Credit Facility, plus a margin of 1.25% to 2.00% (under the 2016 Credit Facility, the margin was from 1.00% to 2.00%), or (b) a Base Rate, as defined in the 2017 Credit Facility, plus a margin of 0.25% to 1.00% (under the 2016 Credit Facility, the margin was from 0.00% to 1.00%). The Base Rate equals the highest of (i) the Federal Funds Rate, as defined in the Credit Facility, plus 0.50%, (ii) Bank of America’s prime rate, and (iii) the Eurocurrency Rate plus 1.00%.
Line of credit facility, commitment fee description				The Company must also pay a commitment fee to the lenders of 0.20% to 0.40% on any unused availability under the Credit Facility.
Line of credit facility, letters of credit issued	305,600,000	$ 314,300,000		$ 305,600,000
Line of credit facility, remaining borrowing capacity	$ 379,800,000			$ 379,800,000
Line of credit facility, unused facility fee (percentage)	0.25%	0.40%
Line of credit facility, collateral				The Credit Facility is guaranteed by certain subsidiaries of the Company (the “Guarantor Subsidiaries”) and the obligations under the Credit Facility are secured by substantially all of the Company’s and the Guarantor Subsidiaries’ respective assets, subject to certain exceptions.
Line of credit facility, covenant terms				The Credit Facility requires that the Company maintain a Maximum Consolidated Leverage Ratio, as defined in the Credit Facility, of 3.50 (subject to the Acquisition Adjustment described below). The Credit Facility also requires that the Company maintain a Minimum Consolidated Interest Coverage Ratio, as defined in the Credit Facility, of 3.00. The Credit Facility provides that, for purposes of calculating the Consolidated Leverage Ratio, certain cash charges may be added back to the calculation of Consolidated EBITDA, as defined in the Credit Facility, and funded indebtedness excludes undrawn standby performance letters of credit. Additionally, notwithstanding the terms discussed above, subject to certain conditions, if a permitted acquisition or series of permitted acquisitions having consideration exceeding $50 million occurs during a fiscal quarter, the Consolidated Leverage Ratio may be temporarily increased to up to 3.75 during such fiscal quarter and the subsequent two fiscal quarters. Such right may be exercised no more than two times during the term of the Credit Facility. Subject to customary exceptions, the Credit Facility limits the borrowers’ and the Guarantor Subsidiaries’ ability to engage in certain activities, including acquisitions, mergers and consolidations, debt incurrence, investments, capital expenditures, asset sales, debt prepayments, lien incurrence and the making of distributions or repurchases of capital stock. However, distributions payable solely in capital stock are permitted. The Credit Facility provides for customary events of default and carries cross-default provisions with the Company’s other significant debt instruments, including the Company’s indemnity agreement with its surety provider, as well as customary remedies, including the acceleration of repayment of outstanding amounts and other remedies with respect to the collateral securing the Credit Facility obligations.
Credit Facility [Member] \| Plan [Member]
Debt Instrument [Line Items]
Line of credit facility, adjusted consolidated leverage ratio, permitted acquisitions amount, minimum threshold				$ 50,000,000
Credit Facility [Member] \| Eurocurrency Rate [Member] \| Base Rate Option (iii) [Member]
Debt Instrument [Line Items]
Line of credit facility, variable interest rate, margin over base rate (percentage)				1.00%
Credit Facility [Member] \| Federal Funds Rate [Member] \| Base Rate Option (i) [Member]
Debt Instrument [Line Items]
Line of credit facility, variable interest rate, margin over base rate (percentage)				0.50%
Credit Facility [Member] \| Bank of America Prime Rate [Member] \| Base Rate Option (ii) [Member]
Debt Instrument [Line Items]
Line of credit facility, variable interest rate, margin over base rate (percentage)				0.00%
Credit Facility [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Line of credit facility, revolving loan sublimit, Canadian dollars or Mexican pesos	$ 300,000,000			$ 300,000,000
Line of credit facility, unused facility fee (percentage)	0.40%	0.40%
Line of credit facility, required consolidated leverage ratio (in multiple)	3.50			3.50
Credit Facility [Member] \| Maximum [Member] \| Plan [Member] \| Permitted Acquisition [Member]
Debt Instrument [Line Items]
Line of credit facility, required consolidated leverage ratio (in multiple)	3.75			3.75
Line of credit facility, adjusted consolidated leverage ratio, permitted acquisitions, maximum number of times right may be exercised	2			2
Credit Facility [Member] \| Maximum [Member] \| Eurocurrency Rate [Member]
Debt Instrument [Line Items]
Line of credit facility, variable interest rate, margin over base rate (percentage)	2.00%	2.00%
Credit Facility [Member] \| Maximum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Line of credit facility, variable interest rate, margin over base rate (percentage)	1.00%	1.00%
Credit Facility [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Line of credit facility, unused facility fee (percentage)	0.20%	0.20%
Line of credit facility, required consolidated interest coverage ratio (in multiple)	3.0			3.0
Credit Facility [Member] \| Minimum [Member] \| Eurocurrency Rate [Member]
Debt Instrument [Line Items]
Line of credit facility, variable interest rate, margin over base rate (percentage)	1.25%	1.00%
Credit Facility [Member] \| Minimum [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Line of credit facility, variable interest rate, margin over base rate (percentage)	0.25%	0.00%
Credit Facility [Member] \| Revolving Loans [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,100,000,000			$ 1,100,000,000
Long-term debt obligations	564,600,000	$ 279,900,000		564,600,000
Line of credit facility, amount of borrowings denominated in foreign currencies	153,000,000	119,000,000		153,000,000
Line of credit facility, remaining borrowing capacity	229,800,000	405,900,000		229,800,000
Line of credit facility, remaining borrowing capacity available in either Canadian dollars or Mexican pesos	$ 147,400,000	$ 80,900,000		$ 147,400,000
Credit Facility [Member] \| Revolving Loans [Member] \| Weighted Average [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	3.60%	3.71%		3.60%
Credit Facility [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 400,000,000			$ 400,000,000
Long-term debt obligations	$ 250,000,000	$ 237,500,000		$ 250,000,000
Line of credit facility, interest rate (percentage)	2.73%	2.77%		2.73%
Line of credit facility, remaining borrowing capacity	$ 150,000,000			$ 150,000,000
Credit Facility [Member] \| Term Loan [Member] \| Plan [Member]
Debt Instrument [Line Items]
Line of credit facility, term loan, frequency of payments				quarterly
Line of credit facility, term loan, amount of quarterly principal installment payments				$ 3,100,000
Credit Facility [Member] \| Term Loan [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Line of credit facility, term loan, proceeds received			$ 150,000,000
Credit Facility [Member] \| Letters of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, capacity available for letters of credit	$ 229,800,000	$ 335,700,000		$ 229,800,000
Line of credit facility, interest rate description, letters of credit				Financial standby letters of credit and commercial letters of credit issued under the 2017 Credit Facility are subject to a letter of credit fee of 1.25% to 2.00% (under the 2016 Credit Facility, the letter of credit fee was from 1.00% to 2.00%), and performance standby letters of credit are subject to a letter of credit fee of 0.50% to 1.00% under the Credit Facility.
Credit Facility [Member] \| Letters of Credit [Member] \| Financial Standby [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	1.50%	2.00%		1.50%
Credit Facility [Member] \| Letters of Credit [Member] \| Performance Standby [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	0.625%	1.00%		0.625%
Credit Facility [Member] \| Letters of Credit [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Line of credit facility, capacity available for letters of credit	$ 650,000,000			$ 650,000,000
Line of credit facility, capacity available for letters of credit sublimit, Canadian dollars or Mexican pesos	$ 200,000,000			$ 200,000,000
Credit Facility [Member] \| Letters of Credit [Member] \| Maximum [Member] \| Financial Standby [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	2.00%	2.00%		2.00%
Credit Facility [Member] \| Letters of Credit [Member] \| Maximum [Member] \| Performance Standby [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	1.00%	1.00%		1.00%
Credit Facility [Member] \| Letters of Credit [Member] \| Minimum [Member] \| Financial Standby [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	1.25%	1.00%		1.25%
Credit Facility [Member] \| Letters of Credit [Member] \| Minimum [Member] \| Performance Standby [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	0.50%	0.50%		0.50%
Credit Facility [Member] \| Swing Line Loans [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Line of credit facility, swing line loans sublimit	$ 75,000,000			$ 75,000,000
Credit Facility [Member] \| Accordion Feature [Member] \| Plan [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 250,000,000			$ 250,000,000

Debt (Other Credit Facilities) (Narrative) (Details) - Other Credit Facilities [Member] $ in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2017 CAD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 CAD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity (in dollars)	$ 20.0		$ 40.0
Debt instrument, rationale for classification as long-term debt	Outstanding borrowings that are not renewed are repaid with borrowings under the Company’s senior secured credit facility. Accordingly, the carrying amounts of the Company’s borrowings under its other credit facilities, which are included within notes payable and other debt obligations in the table above, are classified within long-term debt in the Company’s consolidated balance sheets.
Weighted Average [Member]
Debt Instrument [Line Items]
Line of credit facility, interest rate (percentage)	3.50%	3.50%	3.60%	3.60%
Canadian Dollars [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity (in dollars)		$ 15.4		$ 29.8
Long-term debt obligations (in dollars)		$ 7.0		$ 13.4

Debt (Debt Guarantees and Covenants) (Narrative) (Details) - Senior Notes [Member] - 4.875% Senior Notes [Member]	6 Months Ended
	Jun. 30, 2017
Debt Instrument [Line Items]
Debt instrument, guarantees	The 4.875% Senior Notes are senior unsecured unsubordinated obligations and rank equal in right of payment with existing and future unsubordinated debt, and rank senior in right of payment to existing and future subordinated debt and are fully and unconditionally guaranteed on an unsecured, unsubordinated, joint and several basis by certain of the Company’s existing and future 100%-owned direct and indirect domestic subsidiaries that are each guarantors of the Company’s Credit Facility or other outstanding indebtedness.
Debt instrument, interest rate (percentage)	4.875%

Debt (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
Debt (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Payments of Financing Costs	$ 6.2
Other Accrued Expenses [Member]
Debt Instrument [Line Items]
Debt instruments, accrued interest payable	$ 8.8	$ 8.5

Lease Obligations (Capital Leases) (Narrative) (Details) - Property and Equipment [Member] - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Capital Leases [Line Items]
Assets held under capital lease, gross	$ 395.2	$ 294.9
Assets held under capital lease, net	$ 264.3	$ 177.5

Lease Obligations (Operating Leases) (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Lease Term in Excess of One Year [Member]
Operating Leased Assets [Line Items]
Operating leases, rent and related expense (in dollars)	$ 26.6	$ 24.3	$ 52.2	$ 48.9
Lease Term in Excess of One Year [Member] \| Minimum [Member]
Operating Leased Assets [Line Items]
Operating leases, term of contract (in years)	1 year	1 year	1 year	1 year
Lease Term of One Year or Less [Member]
Operating Leased Assets [Line Items]
Operating leases, rent and related expense (in dollars)	$ 133.3	$ 70.7	$ 188.4	$ 117.2
Lease Term of One Year or Less [Member] \| Maximum [Member]
Operating Leased Assets [Line Items]
Operating leases, term of contract (in years)	1 year	1 year	1 year	1 year

Stock-Based Compensation and Other Employee Benefit Plans (Narrative) (Details) shares in Millions	Jun. 30, 2017 shares
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant	5.0

Stock-Based Compensation and Other Employee Benefit Plans (Restricted Shares) (Narrative) (Details) - Restricted Shares [Member] - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation awards, unearned compensation	$ 19.2	$ 19.2		$ 19.2
Stock-based compensation awards, unearned compensation, weighted average expected recognition period (in years)	1 year 4 months 24 days
Stock-based compensation, vested awards, intrinsic value		$ 0.2	$ 1.2	$ 11.7	$ 1.4

Stock-Based Compensation and Other Employee Benefit Plans (Schedule of Activity, Restricted Shares) (Details) - Common Stock [Member]

6 Months Ended

Jun. 30, 2017

$ / shares

Restricted Shares [Member]

Restricted Shares

Non-vested restricted shares, beginning balance (in shares)

1,970,586

^[1]

Granted (in shares)

188,843

Vested (in shares)

(300,633)

Canceled/forfeited (in shares)

(17,400)

Non-vested restricted shares, ending balance (in shares)

1,841,396

^[1]

Per Share Weighted Average Grant Date Fair Value

Non-vested restricted shares, per share weighted average grant date fair value, beginning balance (in dollars per share) | $ / shares

$ 21.61

Granted (in dollars per share) | $ / shares

39.44

Vested (in dollars per share) | $ / shares

40.73

Canceled/forfeited (in dollars per share) | $ / shares

16.57

Non-vested restricted shares, per share weighted average grant date fair value, ending balance (in dollars per share) | $ / shares

$ 20.36

Restricted Stock Units [Member]

Restricted Shares

Non-vested restricted shares, beginning balance (in shares)

43,300

^[1]

Non-vested restricted shares, ending balance (in shares)

39,050

^[1]

[1]	Includes 39,050 and 43,300 restricted stock units as of June 30, 2017 and December 31, 2016, respectively.

Stock-Based Compensation and Other Employee Benefit Plans (Stock Options) (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised, intrinsic value	$ 0.6	$ 1.3
Stock options exercised, proceeds	$ 0.7	$ 2.0
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation awards, stock options, outstanding (in shares)			0	0

Stock-Based Compensation and Other Employee Benefit Plans (Employee Stock Purchase Plans) (Narrative) (Details)	6 Months Ended
	Jun. 30, 2017
Employee Stock Purchase Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation plans, description	The Company has certain employee stock purchase plans (collectively, “ESPPs”) under which shares of the Company's common stock are available for purchase by eligible employees.

Stock-Based Compensation and Other Employee Benefit Plans (Schedule of Activity, Employee Stock Purchase Plans) (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Common Stock [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Common shares issued (in shares)	49,502	83,680
Employee Stock Purchase Plans [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Cash proceeds (in dollars)	$ 1.6	$ 1.3
Employee Stock Purchase Plans [Member] \| Common Stock [Member]
Stock-Based Compensation and Other Employee Benefit Plans [Line Items]
Weighted average price per share (in dollars per share)	$ 33.30	$ 15.95
Weighted average per share grant date fair value (in dollars per share)	$ 8.67	$ 4.36

Stock-Based Compensation and Other Employee Benefit Plans (Schedule of Non-Cash Stock-Based Compensation Expense and Related Tax Effects) (Details) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2017

Jun. 30, 2016

Jun. 30, 2017

Jun. 30, 2016

Stock-Based Compensation and Other Employee Benefit Plans [Line Items]

Non-cash stock-based compensation expense

$ 7,166

$ 7,405

Income Tax Effects:

Income tax effect of non-cash stock-based compensation

$ 1,300

$ 2,300

2,500

3,900

Excess tax benefit from non-cash stock-based compensation

^[1]

900

100

1,100

Net income tax effect

55,434

17,601

82,792

15,514

ASU 2016-09 [Member]

Income Tax Effects:

Net income tax effect

100

General and Administrative Expenses [Member]

Stock-Based Compensation and Other Employee Benefit Plans [Line Items]

Non-cash stock-based compensation expense

$ 3,400

$ 3,900

$ 7,200

$ 7,400

[1]

Other Retirement Plans (Narrative) (Details)	6 Months Ended
Other Retirement Plans (Narrative) (Details)	Jun. 30, 2017
Multiemployer Plans [Abstract]
Multiemployer plans, general nature	Certain of MasTec’s subsidiaries, including certain subsidiaries in Canada, contribute amounts to multiemployer pension and other multiemployer benefit plans and trusts, which are recorded as a component of employee wages and salaries within costs of revenue, excluding depreciation and amortization. Contributions are generally based on fixed amounts per hour per employee for employees covered under these plans. Multiemployer plan contribution rates are determined annually and assessed on a “pay-as-you-go” basis based on union employee payrolls.

Other Retirement Plans (Schedule of Covered Employees and Contributions, Multiemployer Plans) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) employee	Jun. 30, 2016 USD ($) employee	Jun. 30, 2017 USD ($) employee	Jun. 30, 2016 USD ($) employee
Covered Employees and Contributions, Multiemployer Plans [Line Items]
Multiemployer plans, contributions (in dollars)	$ 31.0	$ 14.7	$ 37.3	$ 21.7
Multiemployer Plans, Pension [Member]
Covered Employees and Contributions, Multiemployer Plans [Line Items]
Multiemployer plans, contributions (in dollars)	28.3	12.2	32.0	17.0
Multiemployer Plans, Other Multiemployer [Member]
Covered Employees and Contributions, Multiemployer Plans [Line Items]
Multiemployer plans, contributions (in dollars)	$ 2.7	$ 2.5	$ 5.3	$ 4.7
Workforce Subject to Collective Bargaining Arrangements [Member] \| Unionized Employees [Member] \| Low [Member]
Covered Employees and Contributions, Multiemployer Plans [Line Items]
Multiemployer plans, covered employees (in number of employees) \| employee	3,669	1,410	550	1,112
Workforce Subject to Collective Bargaining Arrangements [Member] \| Unionized Employees [Member] \| High [Member]
Covered Employees and Contributions, Multiemployer Plans [Line Items]
Multiemployer plans, covered employees (in number of employees) \| employee	7,057	4,170	7,057	4,170

Equity (Share Activity) (Narrative) (Details)	16 Months Ended
Equity (Share Activity) (Narrative) (Details)	Jun. 30, 2017 shares
2016 Share Repurchase Program [Member] \| Treasury Stock, Common [Member]
Equity, Treasury Stock [Line Items]
Common stock repurchases (in shares)	0

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Quarterly provision for income taxes, description	In determining the quarterly provision for income taxes, management uses an estimated annual effective tax rate based on forecasted annual pre-tax income, permanent tax differences, statutory tax rates and tax planning opportunities in the various jurisdictions in which the Company operates. The effect of significant discrete items is separately recognized in the quarter(s) in which they occur.
Long-term deferred tax liabilities, net	$ 252,834	$ 178,355
Current deferred tax assets, net		11,800
Accrued taxes payable, current	$ 16,700	$ 40,300

Segments and Related Information (Narrative) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)
Segments and Related Information [Line Items]
Segment reporting information, factors used to identify entity's reportable segments	MasTec manages its operations under five operating segments, which represent MasTec’s five reportable segments: (1) Communications; (2) Oil and Gas; (3) Electrical Transmission; (4) Power Generation and Industrial and (5) Other. This structure is generally focused on broad end-user markets for MasTec’s labor-based construction services.
Number of operating segments \| segment	5
Number of reportable segments \| segment	5
Segment reporting information, description of products and services	All five reportable segments derive their revenue from the engineering, installation and maintenance of infrastructure, primarily in North America.
Segment reporting, description of all other segments	The Other segment includes equity investees, the services of which vary from those provided by the Company’s four primary segments, as well as other small business units that perform construction and other services for a variety of international end-markets.
Communications [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	The Communications segment performs engineering, construction, maintenance and customer fulfillment activities related to communications infrastructure primarily for wireless and wireline/fiber communications and install-to-the-home customers, and, to a lesser extent, infrastructure for utilities, among others.
Oil and Gas [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	MasTec performs engineering, construction and maintenance services on oil and natural gas pipelines and processing facilities for the energy and utilities industries through its Oil and Gas segment.
Oil and Gas [Member] \| Contracts Accounted for under Percentage-of-Completion [Member]
Segments and Related Information [Line Items]
Project losses (in dollars) \| $		$ 13.5
Electrical Transmission [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	The Electrical Transmission segment primarily serves the energy and utility industries through the engineering, construction and maintenance of electrical transmission lines and substations.
Electrical Transmission [Member] \| Contracts Accounted for under Percentage-of-Completion [Member]
Segments and Related Information [Line Items]
Project losses (in dollars) \| $		$ 15.1
Power Generation and Industrial [Member]
Segments and Related Information [Line Items]
Segment reporting information, description of products and services	The Power Generation and Industrial segment primarily serves energy, utility and other end-markets through the installation and construction of conventional and renewable power facilities, related electrical transmission infrastructure, ethanol/biofuel facilities and various types of industrial infrastructure.
Primary Segments [Member]
Segments and Related Information [Line Items]
Number of operating segments \| segment	4
Other [Member] \| Contracts Accounted for under Percentage-of-Completion [Member] \| Joint Venture [Member] \| Pacer [Member] \| Canadian Dollars [Member]
Segments and Related Information [Line Items]
Project losses (in dollars) \| $	$ 7.0

Segments and Related Information (Schedule of Financial Information by Reportable Segment - Revenue) (Details) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2017

Jun. 30, 2016

Jun. 30, 2017

Jun. 30, 2016

Revenue:

Communications [Member] | Customer Concentration Risk [Member] | Revenue [Member] | Utilities [Member]

$ 1,890,180

$ 1,232,404

$ 3,048,364

$ 2,206,630

Revenue:

Utilities customers, percentage of Communications segment revenue

11.50%

11.00%

12.40%

10.70%

Reportable Segments [Member] | Communications [Member]

Revenue:

Reportable Segments [Member] | Oil and Gas [Member]

^[1]

$ 592,200

$ 1,151,700

$ 1,103,800

Revenue:

Reportable Segments [Member] | Electrical Transmission [Member]

1,140,400

425,600

1,596,200

718,400

Revenue:

Reportable Segments [Member] | Power Generation and Industrial [Member]

96,600

95,600

195,400

181,900

Revenue:

Reportable Segments [Member] | Other [Member]

60,700

119,700

107,300

201,100

Revenue:

1,900

3,900

3,600

7,300

Eliminations [Member]

Revenue:

Communications [Member] | AT&T (including DIRECTV) [Member]

$ (1,600)

$ (4,600)

$ (5,800)

$ (5,900)

[1]	Revenue generated primarily by utilities customers represented 11.5% and 11.0% of Communications segment revenue for the three month periods ended June 30, 2017 and 2016, respectively, and represented 12.4% and 10.7% for the six month periods ended June 30, 2017 and 2016, respectively.

Segments and Related Information (Schedule of Financial Information by Reportable Segment - EBITDA) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
EBITDA:
EBITDA	$ 198.9	$ 95.3	$ 322.4	$ 141.5
Reportable Segments [Member] \| Communications [Member]
EBITDA:
EBITDA	59.5	66.4	107.8	128.1
Reportable Segments [Member] \| Oil and Gas [Member]
EBITDA:
EBITDA	154.0	53.6	247.9	69.8
Reportable Segments [Member] \| Electrical Transmission [Member]
EBITDA:
EBITDA	3.5	(9.9)	6.7	(33.7)
Reportable Segments [Member] \| Power Generation and Industrial [Member]
EBITDA:
EBITDA	4.7	4.8	5.6	7.7
Reportable Segments [Member] \| Other [Member]
EBITDA:
EBITDA	6.8	0.3	1.5	0.5
Corporate [Member]
EBITDA:
EBITDA	$ (29.6)	$ (19.9)	$ (47.1)	$ (30.9)

Segments and Related Information (Schedule of Financial Information by Reportable Segment - Depreciation and Amortization) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Depreciation and Amortization:
Depreciation and amortization	$ 45,379	$ 40,657	$ 88,282	$ 79,664
Reportable Segments [Member] \| Communications [Member]
Depreciation and Amortization:
Depreciation and amortization	13,500	12,400	25,500	24,600
Reportable Segments [Member] \| Oil and Gas [Member]
Depreciation and Amortization:
Depreciation and amortization	23,200	19,300	45,100	37,500
Reportable Segments [Member] \| Electrical Transmission [Member]
Depreciation and Amortization:
Depreciation and amortization	5,700	5,800	11,400	11,000
Reportable Segments [Member] \| Power Generation and Industrial [Member]
Depreciation and Amortization:
Depreciation and amortization	1,400	1,500	2,900	3,100
Reportable Segments [Member] \| Other [Member]
Depreciation and Amortization:
Depreciation and amortization	0	0	100	0
Corporate [Member]
Depreciation and Amortization:
Depreciation and amortization	$ 1,600	$ 1,700	$ 3,300	$ 3,500

Segments and Related Information (Reconciliation of Consolidated Income before Income Taxes to EBITDA) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
EBITDA Reconciliation:
Income before income taxes	$ 138,766	$ 42,039	$ 206,751	$ 37,071
Interest expense, net	14,791	12,639	27,388	24,797
Depreciation and amortization	45,379	40,657	88,282	79,664
Consolidated EBITDA	$ 198,900	$ 95,300	$ 322,400	$ 141,500

Segments and Related Information (Foreign Operations) (Narrative) (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segments and Related Information [Line Items]
Revenue			$ 1,890,180	$ 1,232,404	$ 3,048,364	$ 2,206,630
Property and equipment, net	$ 648,456	$ 549,084	648,456		648,456
Intangible assets and goodwill, net	1,226,200	1,175,600	1,226,200		1,226,200
United States [Member]
Segments and Related Information [Line Items]
Revenue			1,800,000	1,200,000	2,900,000	2,100,000
Property and equipment, net	583,800	475,300	583,800		583,800
Intangible assets and goodwill, net	1,100,000	1,100,000	1,100,000		1,100,000
Foreign Operations [Member]
Segments and Related Information [Line Items]
Revenue			40,500	$ 65,500	99,700	$ 149,000
Property and equipment, net	64,700	73,800	64,700		64,700
Intangible assets and goodwill, net	$ 110,600	$ 107,800	$ 110,600		$ 110,600
Foreign Operations [Member] \| Accounts Receivable, Net, Less Billings in Excess of Costs and Earnings [Member] \| Geographic Concentration Risk [Member] \| Foreign Customers [Member]
Segments and Related Information [Line Items]
Concentration risk, percentage of total	5.00%	8.00%

Segments and Related Information (Schedule of Significant Customers, Revenue Concentration Information) (Details) - Customer Concentration Risk [Member] - Revenue [Member]

3 Months Ended

6 Months Ended

Jun. 30, 2017

Jun. 30, 2016

Jun. 30, 2017

Jun. 30, 2016

Revenue, Significant Customers [Line Items]

Significant customers, percentage of total consolidated revenue

^[1]

22.00%

36.00%

27.00%

37.00%

Oil and Gas [Member] | Energy Transfer Affiliates [Member]

Revenue, Significant Customers [Line Items]

Significant customers, percentage of total consolidated revenue

^[2]

47.00%

22.00%

35.00%

20.00%

[1]

[2]

The Company's relationship with Energy Transfer affiliates is based upon various construction contracts for pipeline activities with Energy Transfer Partners L.P., and their subsidiaries and affiliates, all of which are consolidated by Energy Transfer Equity, L.P. Revenue from Energy Transfer affiliates is included in the Oil and Gas segment.

Commitments and Contingencies (Other Commitments and Contingencies) (Narrative) (Details) $ in Millions, $ in Millions	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jun. 30, 2017 CAD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 CAD ($)	Dec. 31, 2016 USD ($)
Self-Insurance [Member] \| Workers Compensation, General and Automobile Policies [Member]
Commitments and Contingencies [Line Items]
Self-insurance reserve				$ 94.2		$ 85.8
Self-Insurance [Member] \| Workers Compensation, General and Automobile Policies [Member] \| Other Long-Term Liabilities [Member]
Commitments and Contingencies [Line Items]
Self-insurance reserve, non-current				59.5		55.2
Self-Insurance [Member] \| Workers Compensation, General and Automobile Policies [Member] \| Other Long-Term Assets [Member] \| Cash [Member]
Commitments and Contingencies [Line Items]
Cash collateral deposited with insurance carriers				1.5		1.5
Self-Insurance [Member] \| Employee Group Medical Claims Policies [Member]
Commitments and Contingencies [Line Items]
Self-insurance reserve				$ 3.0		2.6
Joint Ventures [Member] \| Joint Venture A That Provides Electrical Transmission Infrastructure Services [Member]
Commitments and Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage			85.00%	85.00%
Joint Ventures [Member] \| Joint Venture B That Provides Electrical Transmission Infrastructure Services [Member]
Commitments and Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage			85.00%	85.00%
Joint Ventures [Member] \| Joint Venture C That Provides Electrical Transmission Infrastructure Services [Member]
Commitments and Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage			90.00%	90.00%
Joint Ventures [Member] \| Joint Ventures That Provide Infrastructure Construction Services For Electrical Transmission Projects [Member]
Commitments and Contingencies [Line Items]
Number of joint ventures			3	3
Joint Ventures [Member] \| Pacer [Member]
Commitments and Contingencies [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage			35.00%	35.00%
Performance and Payment Bonds [Member]
Commitments and Contingencies [Line Items]
Outstanding bonds, amount				$ 50.9		72.9
Performance and Payment Bonds [Member] \| Joint Ventures [Member] \| Pacer [Member]
Commitments and Contingencies [Line Items]
Outstanding bonds, amount			$ 132.1		$ 132.1
Performance and Payment Bonds [Member] \| Estimate [Member]
Commitments and Contingencies [Line Items]
Bonded projects, costs to complete	$ 9.6	$ 9.5
Surety Bond [Member] \| Self-Insurance [Member] \| Workers Compensation [Member]
Commitments and Contingencies [Line Items]
Outstanding bonds, amount				13.5		13.5
Credit Facility [Member]
Commitments and Contingencies [Line Items]
Letters of credit issued				305.6		314.3
Credit Facility [Member] \| Financial Guarantees [Member] \| Self-Insurance [Member] \| Workers Compensation, General and Automobile Policies [Member]
Commitments and Contingencies [Line Items]
Letters of credit issued				$ 85.1		$ 85.1

Commitments and Contingencies (Other Guarantees) (Narrative) (Details)	6 Months Ended
	Jun. 30, 2017
Other Guarantees [Line Items]
General warranty, description	MasTec also generally warrants the work it performs for a one to two year period following substantial completion of a project. Much of the work performed by the Company is evaluated for defects shortly after the work is completed.
Warranty [Member] \| Minimum [Member]
Other Guarantees [Line Items]
General warranty, period (in years)	1 year
Warranty [Member] \| Maximum [Member]
Other Guarantees [Line Items]
General warranty, period (in years)	2 years
Subsidiaries [Member]
Other Guarantees [Line Items]
Other guarantees, description	In the ordinary course of its business, from time to time, MasTec guarantees the obligations of its subsidiaries, including obligations under certain contracts with customers, certain lease obligations and in some states, obligations in connection with obtaining contractors’ licenses.

Commitments and Contingencies (Concentrations of Risk) (Narrative) (Details) - customer			3 Months Ended		6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Concentration Risk [Line Items]
Number of customers					375
Accounts Receivable, Net, Less Billings in Excess of Costs and Earnings [Member] \| Credit Concentration Risk [Member] \| Customer with Highest Net Accounts Receivable Position [Member]
Concentration Risk [Line Items]
Number of customers	1	1
Concentration risk, percentage of total	48.00%	24.00%
Accounts Receivable, Net, Less Billings in Excess of Costs and Earnings [Member] \| Credit Concentration Risk [Member] \| Customer with Second Highest Net Accounts Receivable Position [Member]
Concentration Risk [Line Items]
Concentration risk, percentage of total	11.00%	17.00%
Revenue [Member] \| Customer Concentration Risk [Member] \| Ten Largest Customers [Member]
Concentration Risk [Line Items]
Number of customers			10	10	10	10
Concentration risk, percentage of total			84.00%	76.00%	79.00%	74.00%

Related Party Transactions (Contractual Joint Ventures and Investments) (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Sep. 30, 2017	Jun. 30, 2017 CAD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 CAD ($)	Dec. 31, 2016 USD ($)
Performance Guarantees [Member]
Related Party Transaction [Line Items]
Guarantees issued, related parties							$ 50,900,000		$ 72,900,000
Joint Venture [Member] \| Pacer [Member]
Related Party Transaction [Line Items]
Proportionately consolidated non-controlled joint venture, ownership percentage						35.00%	35.00%
Joint Venture [Member] \| Pacer [Member] \| Performance Guarantees [Member]
Related Party Transaction [Line Items]
Guarantees issued, related parties						$ 132.1		$ 132.1
Joint Venture [Member] \| Pacer [Member] \| Canadian Dollars [Member]
Related Party Transaction [Line Items]
Revenue, related party	$ 200,000	$ 300,000	$ 300,000	$ 600,000
Joint Venture [Member] \| Pacer [Member] \| Canadian Dollars [Member] \| Financing Support [Member]
Related Party Transaction [Line Items]
Payments to affiliate, related party	2,300,000	$ 1,400,000	$ 3,100,000	$ 4,900,000
Amounts committed, related party							$ 0
Joint Venture [Member] \| Pacer [Member] \| Canadian Dollars [Member] \| Performance Guarantees [Member]
Related Party Transaction [Line Items]
Guarantees issued, related parties							101,900,000		98,300,000
Joint Venture [Member] \| Pacer [Member] \| Canadian Dollars [Member] \| Accounts Receivable [Member]
Related Party Transaction [Line Items]
Receivables, related party							800,000		$ 700,000
Equity Investees [Member] \| April 2017 Acquisition [Member]
Related Party Transaction [Line Items]
Receivables, related party							$ 300,000
Payments to affiliate, related party	300,000
Equity method investment, ownership percentage						40.00%	40.00%
Net investment, equity investees							$ 400,000
Equity Investees [Member] \| April 2017 Acquisition [Member] \| Subcontracting Arrangements [Member]
Related Party Transaction [Line Items]
Payments, related party	200,000
Payables, related party							100,000
Management [Member] \| April 2017 Acquisition [Member] \| Financing Arrangements [Member]
Related Party Transaction [Line Items]
Payables, related party							1,400,000
Financing arrangement payments, related party	$ 3,800,000
Chief Executive Officer [Member] \| Plan [Member]
Related Party Transaction [Line Items]
Cost method investment, ownership percentage					4.00%
Chief Executive Officer [Member] \| Cost-method Investments [Member]
Related Party Transaction [Line Items]
Amounts committed, related party							$ 2,000,000

Related Party Transactions (CCI) (Narrative) (Details) - CCI [Member] - Immediate Family Member of Management or Principal Owner [Member] - Equipment [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Related Party Transaction [Line Items]
Payments, related party	$ 11.0	$ 2.8	$ 12.0	$ 3.6
Payables, related party	$ 10.9		$ 10.9		$ 1.5

Related Party Transactions (Other Related Party Transactions) (Narrative) (Details)	3 Months Ended			6 Months Ended
	Jun. 30, 2017 USD ($) employee	Mar. 31, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) employee	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Related Party Transaction [Line Items]
Distributions to non-controlling interests		$ 1,300,000		$ 1,280,000	$ 0
Management [Member] \| Subcontracting Arrangement, Construction Services [Member]
Related Party Transaction [Line Items]
Number of subsidiaries, non-controlling interests, subcontracting arrangement				1
Management [Member] \| Subcontracting Arrangement, Construction Services [Member] \| Related Contractor [Member]
Related Party Transaction [Line Items]
Number of additional management employees, subcontracting arrangement \| employee	2			2
Payments, related party	$ 15,000,000		$ 1,800,000	$ 15,500,000	3,300,000
Payables, related party	6,500,000			6,500,000		$ 100,000
Management [Member] \| Service Agreements [Member]
Related Party Transaction [Line Items]
Payments, related party	7,900,000		3,600,000	14,500,000	6,800,000
Payables, related party	3,900,000			3,900,000		3,700,000
Management [Member] \| Lease Agreements [Member]
Related Party Transaction [Line Items]
Payments, related party	14,400,000		9,900,000	27,100,000	19,100,000
Payables, related party	200,000			200,000		300,000
Executive Officers [Member] \| Employee Leasing Arrangements [Member] \| Related Customer [Member]
Related Party Transaction [Line Items]
Charges, related party	200,000		200,000	400,000	400,000
Receivables, related party	200,000			200,000		200,000
Executive Officers [Member] \| Service Agreements [Member] \| Related Customer [Member]
Related Party Transaction [Line Items]
Revenue, related party	200,000		200,000	400,000	400,000
Accounts receivable, related party	300,000			300,000		$ 400,000
Chairman, Board of Directors [Member] \| Lease Agreements [Member] \| Aircraft [Member]
Related Party Transaction [Line Items]
Payments, related party	500,000		$ 600,000	1,000,000	$ 1,300,000
Payables, related party	$ 0			$ 0

Related Party Transactions (Split Dollar Agreements) (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Chief Executive Officer [Member]
Related Party Transaction [Line Items]
Payments for life insurance policies	$ 0.7	$ 0.7
Chairman, Board of Directors [Member]
Related Party Transaction [Line Items]
Payments for life insurance policies	0.5	$ 0.5
Executive Officers [Member] \| Other Long-Term Assets [Member]
Related Party Transaction [Line Items]
Life insurance assets, carrying amount	$ 16.0		$ 14.8

Supplemental Guarantor Financial Information (Narrative) (Details)	Jun. 30, 2017
Senior Notes [Member] \| 4.875% Senior Notes [Member]
Condensed Unaudited Consolidating Financial Information [Line Items]
Debt instrument, interest rate (percentage)	4.875%

Supplemental Guarantor Financial Information (Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss)) (Details) - USD ($)
$ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2017

Jun. 30, 2016

Jun. 30, 2017

Jun. 30, 2016

Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]

Costs of revenue, excluding depreciation and amortization

$ 1,890,180

$ 1,232,404

$ 3,048,364

$ 2,206,630

1,626,335

1,068,182

2,597,469

1,952,583

45,379

40,657

88,282

79,664

70,823

67,852

135,604

127,900

Equity in (earnings) losses of unconsolidated affiliates

14,791

12,639

27,388

24,797

(6,060)

(489)

(7,706)

(3,555)

146

1,524

576

(11,830)

138,766

42,039

206,751

37,071

Net income (loss) before equity in income from subsidiaries

(55,434)

(17,601)

(82,792)

(15,514)

83,300

24,400

124,000

21,600

Equity in income (losses) from subsidiaries, net of tax

Net income attributable to non-controlling interests

83,332

24,438

123,959

21,557

1,664

350

1,321

162

^[1]

81,668

24,088

122,638

21,395

Reportable Legal Entities [Member] | MasTec, Inc. [Member]

81,197

20,108

123,638

14,841

Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]

Costs of revenue, excluding depreciation and amortization

600

1,200

Equity in (earnings) losses of unconsolidated affiliates

(600)

(1,200)

Net income (loss) before equity in income from subsidiaries

200

400

500

(400)

(800)

(700)

Equity in income (losses) from subsidiaries, net of tax

82,100

24,400

123,400

22,100

Net income attributable to non-controlling interests

81,700

24,000

122,600

21,400

81,700

24,000

122,600

21,400

Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]

79,500

19,800

122,300

14,700

Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]

Costs of revenue, excluding depreciation and amortization

1,818,100

1,149,400

2,903,200

2,027,700

1,566,300

995,000

2,457,400

1,772,300

37,100

31,700

71,100

63,000

66,500

61,500

126,000

111,500

Equity in (earnings) losses of unconsolidated affiliates

30,400

27,800

58,300

55,200

(5,300)

1,800

(5,300)

(9,400)

123,100

31,600

195,700

35,100

Net income (loss) before equity in income from subsidiaries

(44,700)

(12,600)

(71,300)

(14,000)

78,400

19,000

124,400

21,100

Equity in income (losses) from subsidiaries, net of tax

Net income attributable to non-controlling interests

78,400

19,000

124,400

21,100

78,400

19,000

124,400

21,100

Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]

78,400

19,000

124,400

21,100

Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]

Costs of revenue, excluding depreciation and amortization

122,900

93,500

217,000

189,500

110,800

83,700

211,900

190,900

8,300

9,000

17,200

16,700

3,700

5,800

8,400

15,200

Equity in (earnings) losses of unconsolidated affiliates

(15,600)

(15,200)

(30,900)

(30,400)

(6,100)

(500)

(7,700)

(3,600)

5,400

(300)

5,900

(2,400)

16,300

11,000

12,300

3,100

Net income (loss) before equity in income from subsidiaries

(10,900)

(5,200)

(11,900)

(2,000)

5,400

5,800

400

1,100

Equity in income (losses) from subsidiaries, net of tax

Net income attributable to non-controlling interests

5,400

5,800

400

1,100

1,700

400

1,300

200

3,700

5,400

(1,000)

900

Condensed Unaudited Consolidating Statements of Operations and Comprehensive Income (Loss) [Line Items]

3,200

1,400

(5,600)

Eliminations [Member]

Costs of revenue, excluding depreciation and amortization

(50,800)

(10,500)

(71,800)

(10,600)

(50,800)

(10,500)

(71,800)

(10,600)

Equity in (earnings) losses of unconsolidated affiliates

Net income (loss) before equity in income from subsidiaries

Equity in income (losses) from subsidiaries, net of tax

(82,100)

(24,400)

(123,400)

(22,100)

Net income attributable to non-controlling interests

(82,100)

(24,400)

(123,400)

(22,100)

(82,100)

(24,400)

(123,400)

(22,100)