Quanta Services (PWR) 10-K 29 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Feb. 23, 2016	Jun. 30, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	PWR
Entity Registrant Name	QUANTA SERVICES INC
Entity Central Index Key	1,050,915
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		152,907,166
Entity Public Float			$ 5.7
Series F Preferred Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1
Series G Preferred Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1
Exchangeable Shares Associated with Series F Preferred Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,500,000
Exchangeable Shares Associated with Series G Preferred Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		449,929
Exchangeable Shares Not Associated with Preferred Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		2,926,113

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current Assets:
Cash and cash equivalents	$ 128,771	$ 190,515
Accounts receivable, net of allowances of $5,226 and $6,174	1,621,133	1,801,110
Costs and estimated earnings in excess of billings on uncompleted contracts	317,745	290,447
Inventories	75,285	38,921
Prepaid expenses and other current assets	134,585	161,024
Current assets of discontinued operations		13,687
Total current assets	2,277,519	2,495,704
Property and equipment, net of accumulated depreciation of $755,272 and $651,559	1,101,959	1,099,574
Other assets, net	76,333	78,964
Other intangible assets, net of accumulated amortization of $264,674 and $225,367	205,074	243,584
Goodwill	1,552,658	1,596,695
Non-current assets of discontinued operations		739,062
Total assets	5,213,543	6,253,583
Current Liabilities:
Current maturities of long-term debt and short-term borrowings	7,067	8,876
Accounts payable and accrued expenses	782,134	825,231
Billings in excess of costs and estimated earnings on uncompleted contracts	399,230	251,113
Current liabilities of discontinued operations	15,313	21,091
Total current liabilities	1,203,744	1,106,311
Long-term debt and notes payable, net of current maturities	475,364	72,489
Deferred income taxes	186,491	215,981
Insurance and other non-current liabilities	260,129	227,730
Non-current liabilities of discontinued operations		105,532
Total liabilities	$ 2,125,728	$ 1,728,043
Commitments and Contingencies
Equity:
Common stock, value	$ 2	$ 2
Additional paid-in capital	3,497,740	3,592,906
Retained earnings	1,677,698	1,366,791
Accumulated other comprehensive income (loss)	(294,689)	(123,290)
Treasury stock, 74,991,343 and 15,374,866 common shares, at cost	(1,795,257)	(321,936)
Total stockholders' equity	3,085,494	4,514,473
Non-controlling interests	2,321	11,067
Total equity	3,087,815	4,525,540
Total liabilities and equity	$ 5,213,543	$ 6,253,583
Exchangeable Shares [Member]
Equity:
Common stock, value
Series F Preferred Stock [Member]
Equity:
Preferred Stock, value
Series G Preferred Stock [Member]
Equity:
Preferred Stock, value

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Allowances on accounts receivable, current	$ 5,226	$ 6,174
Accumulated depreciation on property and equipment	755,272	651,559
Accumulated amortization on other intangible assets	$ 264,674	$ 225,367
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	227,898,509	226,194,656
Common stock, shares outstanding	152,907,166	210,819,790
Treasury stock, common shares	74,991,343	15,374,866
Exchangeable Shares [Member]
Exchangeable Shares, par value
Common stock, shares issued	6,876,042	7,325,971
Common stock, shares outstanding	6,876,042	7,325,971
Series F Preferred Stock [Member]
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	1	1
Preferred stock, shares issued	1	1
Preferred stock, shares outstanding	1	1
Series G Preferred Stock [Member]
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	1	1
Preferred stock, shares issued	1	1
Preferred stock, shares outstanding	1	1

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenues	$ 7,572,436	$ 7,747,229	$ 6,411,577
Cost of services (including depreciation)	6,648,771	6,578,435	5,424,644
Gross profit	923,665	1,168,794	986,933
Selling, general and administrative expenses	592,863	705,477	485,069
Amortization of intangible assets	34,848	34,257	25,865
Asset impairment charges	58,451
Operating income	237,503	429,060	475,999
Interest expense	(8,024)	(4,765)	(2,668)
Interest income	1,493	3,736	3,378
Equity in earnings (losses) of unconsolidated affiliates, including gain on sale of investment	(466)	(332)	112,744
Other income (expense), net	(1,831)	(1,100)	(1,133)
Income from continuing operations before income taxes	228,675	426,599	588,320
Provision for income taxes	97,472	139,007	196,875
Net income from continuing operations	131,203	287,592	391,445
Net income from discontinued operations	190,621	27,490	29,864
Net income	321,824	315,082	421,309
Less: Net income attributable to non-controlling interests	10,917	18,368	19,388
Net income attributable to common stock	310,907	296,714	401,921
Amounts attributable to common stock:
Net income from continuing operations	120,286	269,224	372,057
Net income from discontinued operations	190,621	27,490	29,864
Net income attributable to common stock	$ 310,907	$ 296,714	$ 401,921
Earnings per share attributable to common stock- basic and diluted:
Continuing operations	$ 0.62	$ 1.22	$ 1.73
Discontinued operations	0.97	0.13	0.14
Net income attributable to common stock	$ 1.59	$ 1.35	$ 1.87
Shares used in computing earnings per share:
Weighted average basic shares outstanding	195,113	219,668	214,929
Weighted average diluted shares outstanding	195,120	219,690	214,978

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 321,824	$ 315,082	$ 421,309
Other comprehensive income (loss), net of tax provision:
Foreign currency translation adjustment, net of tax of $0, $0 and $0	(171,458)	(84,505)	(54,553)
Other, net of tax of $(28), $486 and $(934)	59	(1,549)	2,864
Other comprehensive income (loss)	(171,399)	(86,054)	(51,689)
Comprehensive income	150,425	229,028	369,620
Less: Comprehensive income attributable to non-controlling interests	10,917	18,368	19,388
Total comprehensive income attributable to Quanta stockholders	$ 139,508	$ 210,660	$ 350,232

Consolidated Statements of Com6

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment, tax	$ 0	$ 0	$ 0
Other comprehensive income other tax	$ (28)	$ 486	$ (934)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash Flows from Operating Activities of Continuing Operations:
Net income	$ 321,824	$ 315,082	$ 421,309
Adjustments to reconcile net income to net cash provided by operating activities of continuing operations -
Income from discontinued operations	(190,621)	(27,490)	(29,864)
Depreciation	162,845	141,106	118,830
Amortization of intangible assets	34,848	34,257	25,865
Asset impairment charges	58,451
Equity in (earnings) losses of unconsolidated affiliates, including gain on sale of investment	466	332	(112,744)
Amortization of debt issuance costs	1,251	1,094	1,081
Gain on sale of property and equipment	(2,773)	(1,803)	(2,464)
Foreign currency loss	2,490	1,244	2,179
Provision for doubtful accounts	224	1,411	3,236
Provision for contract receivable		102,460
Non-cash portion of arbitration expense		10,518
Deferred income tax provision (benefit)	(19,403)	22,906	(25,713)
Non-cash stock-based compensation	36,939	37,449	34,381
Tax impact of stock-based equity awards	(669)	(1,563)	(3,723)
Changes in operating assets and liabilities, net of non-cash transactions - (Increase) decrease in -
Accounts and notes receivable	150,470	(239,159)	(69,599)
Costs and estimated earnings in excess of billings on uncompleted contracts	(49,358)	(73,443)	(42,273)
Inventories	(33,524)	(4,025)	5,986
Prepaid expenses and other current assets	5,899	(35,493)	(10,329)
Accounts payable and accrued expenses and other non-current liabilities	(2,486)	(60,829)	19,254
Billings in excess of costs and estimated earnings on uncompleted contracts	153,017	28,596	38,708
Other, net	(11,707)	(4,908)	(3,562)
Net cash provided by operating activities of continuing operations	618,183	247,742	370,558
Cash Flows from Investing Activities of Continuing Operations:
Proceeds from sale of property and equipment	26,178	14,448	14,789
Additions of property and equipment	(209,968)	(247,216)	(221,946)
Cash paid for acquisitions, net of cash acquired	(112,914)	(262,218)	(283,837)
Investments in and return of equity from unconsolidated affiliates	(6,074)	(3,127)	186,185
Cash received from (paid for) other investments, net	(4,338)	6,214	(10,032)
Cash withdrawn from restricted cash	214	3,565	36,482
Cash paid for intangibles	(211)	(252)
Net cash used in investing activities of continuing operations	(307,113)	(488,586)	(278,359)
Cash Flows from Financing Activities of Continuing Operations:
Borrowings under credit facility	3,349,385	938,047	341,730
Payments under credit facility	(2,935,752)	(866,224)	(341,730)
Borrowings of other long-term debt		394	23
Payments on other long-term debt	(2,683)	(30,448)	(556)
Borrowings of short-term debt	4,872	5,056
Payments on short-term debt	(5,170)
Debt issuance and amendment costs	(3,795)		(3,244)
Contributions from non-controlling interests	2,313
Distributions to non-controlling interests	(21,228)	(14,432)	(17,625)
Tax impact of stock-based equity awards	669	1,563	3,723
Exercise of stock options	372	1,179	1,028
Repurchase of common stock, including accelerated stock repurchases	(1,606,361)	(93,482)
Net cash used in financing activities of continuing operations	(1,217,378)	(58,347)	(16,651)
Discontinued operations:
Net cash provided by operating activities	22,342	63,082	76,034
Net cash provided by provided by (used in) investing activities	825,376	(54,280)	(41,607)
Net cash provided by discontinued operations	847,718	8,802	34,427
Effect of foreign exchange rate changes on cash and cash equivalents	(3,154)	(7,873)	(15,899)
Net increase (decrease) in cash and cash equivalents	(61,744)	(298,262)	94,076
Cash and cash equivalents, beginning of year	190,515	488,777	394,701
Cash and cash equivalents, end of year	128,771	190,515	488,777
Supplemental disclosure of cash flow information:
Interest paid related to continuing operations	(7,087)	(3,533)	(1,586)
Income taxes paid	(130,921)	(223,901)	(244,550)
Income tax refunds related to continuing operations	23,788	7,376	1,826
Discontinued Operations [Member]
Supplemental disclosure of cash flow information:
Income taxes paid	$ (144,076)	$ (5,286)	$ (8,625)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Exchangeable Shares [Member]	Series F Preferred Stock [Member]	Series G Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total Stockholders' Equity [Member]	Non-controlling Interests [Member]
Balance at Dec. 31, 2012	$ 3,771,916				$ 2	$ 3,287,086	$ 668,156	$ 14,453	$ (203,149)	$ 3,766,548	$ 5,368
Balance, Shares at Dec. 31, 2012		3,909,110	1		209,270,586
Other comprehensive income (loss)	(51,689)							(51,689)		(51,689)
Acquisitions	88,896					88,896				88,896
Acquisitions, shares					3,547,482
Restricted stock activity	23,785					35,876			(12,091)	23,785
Restricted stock activity, shares					(358,753)
Stock options exercised	1,028					1,028				1,028
Stock options exercised, shares					74,342
Exchange of exchangeable shares		(409,110)			409,110
Income tax benefit (expense) from long-term incentive plans	3,699					3,699				3,699
Distributions to non-controlling interests	(17,625)										(17,625)
Net income	421,309						401,921			401,921	19,388
Balance at Dec. 31, 2013	4,241,319				$ 2	3,416,585	1,070,077	(37,236)	(215,240)	4,234,188	7,131
Balance, Shares at Dec. 31, 2013		3,500,000	1		212,942,767
Other comprehensive income (loss)	(86,054)							(86,054)		(86,054)
Acquisitions	134,538					134,538				134,538
Acquisitions, shares		3,825,971		1	686,382
Restricted stock activity	26,690					39,030			(12,340)	26,690
Restricted stock activity, shares					95,475
Stock options exercised	1,179					1,179				1,179
Stock options exercised, shares					91,444
Income tax benefit (expense) from long-term incentive plans	700					700				700
Common stock repurchases	(93,482)								(93,482)	(93,482)
Common stock repurchases, shares					(2,996,278)
Deferral plan shares						874			(874)
Distributions to non-controlling interests	(14,432)										(14,432)
Net income	315,082						296,714			296,714	18,368
Balance at Dec. 31, 2014	4,525,540				$ 2	3,592,906	1,366,791	(123,290)	(321,936)	4,514,473	11,067
Balance, Shares at Dec. 31, 2014		7,325,971	1	1	210,819,790
Other comprehensive income (loss)	(171,399)							(171,399)		(171,399)
Acquisitions	9,379					10,127				10,127	(748)
Acquisitions, shares					461,037
Restricted stock activity	26,941					37,309			(10,368)	26,941
Restricted stock activity, shares					395,427
Stock options exercised	431					431				431
Stock options exercised, shares					32,390
Exchange of exchangeable shares		(449,929)			449,929
Income tax benefit (expense) from long-term incentive plans	375					375				375
Common stock repurchases	(1,456,361)								(1,456,361)	(1,456,361)
Common stock repurchases, shares					(59,251,407)
Accelerated stock repurchases not yet settled	(150,000)					(150,000)				(150,000)
Deferral plan shares						6,592			(6,592)
Contributions from non-controlling interests	2,313										2,313
Distributions to non-controlling interests	(21,228)										(21,228)
Net income	321,824						310,907			310,907	10,917
Balance at Dec. 31, 2015	$ 3,087,815				$ 2	$ 3,497,740	$ 1,677,698	$ (294,689)	$ (1,795,257)	$ 3,085,494	$ 2,321
Balance, Shares at Dec. 31, 2015		6,876,042	1	1	152,907,166

Business and Organization

Business and Organization	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Organization	1. BUSINESS AND ORGANIZATION: Quanta Services, Inc. (Quanta) is a leading provider of specialty contracting services, offering infrastructure solutions primarily to the electric power and oil and gas industries in the United States, Canada and Australia and select other international markets. Quanta reports its results under two reportable segments: (1) Electric Power Infrastructure Services and (2) Oil and Gas Infrastructure Services. Electric Power Infrastructure Services Segment The Electric Power Infrastructure Services segment provides comprehensive network solutions to customers in the electric power industry. Services performed by the Electric Power Infrastructure Services segment generally include the design, installation, upgrade, repair and maintenance of electric power transmission and distribution infrastructure and substation facilities along with other engineering and technical services. This segment also provides emergency restoration services, including the repair of infrastructure damaged by inclement weather, the energized installation, maintenance and upgrade of electric power infrastructure utilizing unique bare hand and hot stick methods and Quanta’s proprietary robotic arm technologies, and the installation of “smart grid” technologies on electric power networks. In addition, this segment designs, installs and maintains renewable energy generation facilities, consisting of solar, wind and certain types of natural gas generation facilities, and related switchyards and transmission infrastructure to transport power to demand centers. To a lesser extent, this segment provides services such as the construction of electric power generation facilities, the design, installation, maintenance and repair of commercial and industrial wiring, installation of traffic networks, the installation of cable and control systems for light rail lines and limited ancillary telecommunication infrastructure services. Oil and Gas Infrastructure Services Segment The Oil and Gas Infrastructure Services segment provides comprehensive network solutions to customers involved in the development and transportation of natural gas, oil and other pipeline products. Services performed by the Oil and Gas Infrastructure Services segment generally include the design, installation, repair and maintenance of pipeline transmission and distribution systems, gathering systems, production systems and compressor and pump stations, as well as related trenching, directional boring and automatic welding services. In addition, this segment’s services include pipeline protection, integrity testing, rehabilitation and replacement and fabrication of pipeline support systems and related structures and facilities. Quanta also serves the offshore and inland water energy markets, primarily providing services to oil and gas exploration platforms, including mechanical installation (or “hook-ups”), electrical and instrumentation, pre-commissioning and commissioning, coatings, fabrication, pipeline construction, integrity services and marine asset repair. To a lesser extent, this segment designs, installs and maintains fueling systems as well as water and sewer infrastructure. Disposition—Fiber Optic Licensing Operations On April 29, 2015, Quanta entered into a stock purchase agreement with Crown Castle International Corp., pursuant to which Quanta agreed to sell its fiber optic licensing operations. The purchase agreement contained customary representations and warranties, covenants and indemnities. On August 4, 2015, Quanta completed the sale for a purchase price of approximately $1 billion in cash, resulting in after-tax net proceeds of approximately $848 million. In the third quarter of 2015, Quanta recognized a net of tax gain of approximately $171 million. Quanta has presented the results of operations, financial position, cash flows and disclosures of the fiber optic licensing operations as discontinued operations for all periods in the accompanying consolidated financial statements. These results were included in Quanta’s Fiber Optic Licensing and Other segment prior to the second quarter of 2015. Acquisitions During 2015, Quanta acquired 11 companies. The results of eight of the acquired companies are generally included in Quanta’s Electric Power Infrastructure Services segment. These companies include a foundation services company located in the United States, an electrical contracting company located in the United States, an electrical engineering company located in Australia, a powerline construction company located in the United States, an engineering company located in Canada, an engineering, procurement and construction services company based in the United States, an underground construction contracting company located in Canada, and a supplier and material procurement specialist for the power and utility industry in Canada. The results of the remaining three acquired companies are generally included in Quanta’s Oil and Gas Infrastructure Services segment. These companies include a company that services above-ground storage tanks in the United States, an underground utility distribution contractor that provides services to gas and electric utilities in Canada, and a company that specializes in the engineering, procurement, construction, and commissioning of compression and surface facilities for the high pressure gas industry in Australia. During 2014, Quanta completed nine acquisitions, which enabled Quanta to further enhance its electric power and oil and gas infrastructure service offerings in the United States and Canada and expand its capabilities in Australia to include electric power infrastructure service offerings. These acquisitions included four electric power infrastructure services companies located in Canada; two oil and gas infrastructure services businesses located in Canada; an electric power infrastructure services company located in Australia; a U.S. based general engineering and construction company specializing in hydrant fueling, waterfront and utility construction for the U.S. Department of Defense the results of which are generally included in Quanta’s Oil and Gas Infrastructure Services segment; and a geotechnical and geological engineering services company based in the United States the results of which are generally included in Quanta’s Electric Power Infrastructure Services segment. During 2013, Quanta acquired six businesses, which included three electric power infrastructure services companies and three oil and gas infrastructure services companies based throughout the United States, Canada and Australia.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES: Principles of Consolidation The consolidated financial statements of Quanta include the accounts of Quanta Services, Inc. and its wholly owned subsidiaries, which are also referred to as its operating units. The consolidated financial statements also include the accounts of certain of Quanta’s investments in joint ventures, which are either consolidated or proportionately consolidated, as discussed in the following summary of significant accounting policies. Investments in affiliated entities in which Quanta does not have a controlling financial interest, but over which Quanta has significant influence, usually because Quanta holds a voting interest of between 20% and 50%, are accounted for using the equity method. All significant intercompany accounts and transactions have been eliminated in consolidation. Unless the context requires otherwise, references to Quanta include Quanta Services, Inc. and its consolidated subsidiaries. Use of Estimates and Assumptions The preparation of financial statements in conformity with US GAAP requires the use of estimates and assumptions by management in determining the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities known to exist as of the date the financial statements are published, and the reported amounts of revenues and expenses recognized during the periods presented. Quanta reviews all significant estimates affecting its consolidated financial statements on a recurring basis and records the effect of any necessary adjustments prior to their publication. Judgments and estimates are based on Quanta’s beliefs and assumptions derived from information available at the time such judgments and estimates are made. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of financial statements. Estimates are primarily used in Quanta’s assessment of the allowance for doubtful accounts, valuation of inventory, useful lives of assets, fair value assumptions in analyzing goodwill, other intangibles and long-lived asset impairments, equity and other investments, loan receivables, purchase price allocations, liabilities for self-insured and other claims and guarantees, multiemployer pension plan withdrawal liabilities, revenue recognition for construction contracts inclusive of contractual change orders and claims, share-based compensation, operating results of reportable segments, as well as the provision for income taxes and the calculation of uncertain tax positions. Cash and Cash Equivalents Quanta had cash and cash equivalents of $128.8 million and $190.5 million as of December 31, 2015 and 2014. Cash consisting of interest-bearing demand deposits is carried at cost, which approximates fair value. Quanta considers all highly liquid investments with an original maturity of three months or less at the time of purchase to be cash equivalents, which are carried at fair value. At December 31, 2015 and 2014, cash equivalents were $1.4 million and $107.6 million and consisted primarily of money market mutual funds and are discussed further in Fair Value Measurements Current and Long-Term Accounts and Notes Receivable and Allowance for Doubtful Accounts Quanta provides an allowance for doubtful accounts when collection of an account or note receivable is considered doubtful, and receivables are written off against the allowance when deemed uncollectible. Inherent in the assessment of the allowance for doubtful accounts are certain judgments and estimates regarding, among other factors, the customer’s access to capital, the customer’s willingness or ability to pay, general economic and market conditions, the ongoing relationship with the customer and uncertainties related to the resolution of disputed matters. Quanta considers accounts receivable delinquent after 30 days but does not generally include delinquent accounts in its analysis of the allowance for doubtful accounts unless the accounts receivable have been outstanding for at least 90 days. In addition to balances that have been outstanding for 90 days or more, Quanta also includes accounts receivable balances that relate to customers in bankruptcy or with other known difficulties in its analysis of the allowance for doubtful accounts. Material changes in Quanta’s customers’ business or cash flows, which may be impacted by negative economic and market conditions, could affect Quanta’s ability to collect amounts due from them. As of December 31, 2015 and 2014, Quanta had allowances for doubtful accounts on current receivables of approximately $5.2 million and $6.2 million. Long-term accounts receivable are included within other assets, net on the consolidated balance sheets. Should customers experience financial difficulties or file for bankruptcy, or should anticipated recoveries relating to receivables in existing bankruptcies or other workout situations fail to materialize, Quanta could experience reduced cash flows and losses in excess of current allowances provided. The balances billed but not paid by customers pursuant to retainage provisions in certain contracts are generally due upon completion of the contracts and acceptance by the customer. Based on Quanta’s experience with similar contracts in recent years, the majority of the retainage balances at each balance sheet date are expected to be collected within the next twelve months. Current retainage balances as of December 31, 2015 and 2014 were approximately $250.1 million and $307.3 million and were included in accounts receivable. Retainage balances with settlement dates beyond the next twelve months were included in other assets, net, and as of December 31, 2015 and 2014 were $4.5 million and $19.6 million. Within accounts receivable, Quanta recognizes unbilled receivables in circumstances such as when revenues have been earned and recorded but the amount cannot be billed under the terms of the contract until a later date; costs have been incurred but are yet to be billed under cost-reimbursement type contracts; or amounts arise from routine lags in billing (for example, work completed one month but not billed until the next month). These balances do not include revenues accrued for work performed under fixed-price contracts as these amounts are recorded as costs and estimated earnings in excess of billings on uncompleted contracts. At December 31, 2015 and 2014, the balances of unbilled receivables included in accounts receivable were approximately $233.6 million and $163.1 million. Inventories Inventories consist primarily of parts and supplies held for use in the ordinary course of business, which are valued by Quanta at the lower of cost or market as determined by using either the first-in, first-out (FIFO) method or the average costing method. Inventories also include certain job specific materials not yet installed which are valued using the specific identification method. Property and Equipment Property and equipment are stated at cost, and depreciation is computed using the straight-line method, net of estimated salvage values, over the estimated useful lives of the assets. Leasehold improvements are capitalized and amortized over the lesser of the life of the lease or the estimated useful life of the asset. Depreciation expense related to property and equipment was approximately $162.8 million, $141.1 million and $118.8 million for the years ended December 31, 2015, 2014 and 2013, respectively. Accrued capital expenditures were $5.8 million and $11.8 million as of December 31, 2015 and 2014. The impact of these items has been excluded from Quanta’s capital expenditures on its consolidated statements of cash flows due to their non-cash nature. Expenditures for repairs and maintenance are charged to expense when incurred. Expenditures for major renewals and betterments, which extend the useful lives of existing equipment, are capitalized and depreciated over the adjusted remaining useful lives of the assets. Upon retirement or disposition of property and equipment, the cost and related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in selling, general and administrative expenses. Management reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount may not be realizable. Quanta recognized an impairment charge of $6.6 million during the quarter ended December 31, 2015 related to certain of Quanta’s international renewable energy services operations based on the estimated future undiscounted cash flows associated with the asset group as compared to the carrying value before the impairment. Quanta did not recognize any asset impairments during the years ended December 31, 2014 or 2013. When an evaluation is required, the estimated future undiscounted cash flows associated with the asset group are compared to the asset group’s carrying amount to determine if an impairment of such asset group is necessary. The effect of any impairment involves expensing the difference between the fair value of such asset group and its carrying value in the period incurred. Other Assets, Net Other assets, net consists primarily of long-term receivables, debt issuance costs, equity and other investments, refundable security deposits for leased properties and insurance claims in excess of deductibles that are due from Quanta’s insurers. Debt Issuance Costs Capitalized debt issuance costs related to Quanta’s credit facility and any other debt outstanding at a given balance sheet date are included in other assets, net and are amortized into interest expense on a straight-line basis over the terms of the respective agreements giving rise to the debt issuance costs, which Quanta believes approximates the effective interest rate method. During 2015, Quanta incurred $3.8 million of debt issuance costs related to the amendment and restatement of its credit agreement and recorded a nominal charge to interest expense for the write-off of a portion of the debt issuance costs related to the prior facility. During 2013, Quanta incurred $3.2 million of debt issuance costs related to the amendment and restatement of its credit agreement and recorded a nominal charge to interest expense for the write-off of a portion of the debt issuance costs related to the prior facility. As of December 31, 2015 and 2014, capitalized debt issuance costs were $11.4 million and $7.6 million, with accumulated amortization of $4.8 million and $3.5 million. For the years ended December 31, 2015, 2014 and 2013, amortization expense related to capitalized debt issuance costs was $1.3 million, $1.1 million and $1.1 million, respectively. Goodwill and Other Intangibles Quanta has recorded goodwill in connection with its historical acquisitions of companies. Upon acquisition, these companies were either combined into one of Quanta’s existing operating units or managed on a stand-alone basis as an individual operating unit. Goodwill recorded in connection with these acquisitions is subject to an annual assessment for impairment, which Quanta performs at the operating unit level for each operating unit that carries a balance of goodwill. Each of Quanta’s operating units is organized into one of two internal divisions: the Electric Power Infrastructure Services Division and the Oil and Gas Infrastructure Services Division. As most of the companies acquired by Quanta provide multiple types of services for multiple types of customers, these divisional designations are based on the predominant type of work performed by each operating unit at the point in time the divisional designation is made. Goodwill is required to be measured for impairment at the reporting unit level, which represents the operating segment level or one level below the operating segment level for which discrete financial information is available. Quanta has determined that its individual operating units represent its reporting units for the purpose of assessing goodwill impairments. Quanta has the option to first assess qualitative factors to determine whether it is necessary to perform the two-step fair value-based impairment test described below. If Quanta believes that, as a result of its qualitative assessment, it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the quantitative impairment test is required. Otherwise, no further testing is required. Quanta can choose to perform the qualitative assessment on none, some or all of its reporting units. Quanta can also bypass the qualitative assessment for any reporting unit in any period and proceed directly to step one of the impairment test, and then resume the qualitative assessment in any subsequent period. Qualitative indicators including deterioration in macroeconomic conditions, declining financial performance, or a sustained decrease in share price, among other things, may trigger the need for annual or interim impairment testing of goodwill associated with one or all of the reporting units. Quanta’s goodwill impairment assessment is performed at year-end, or more frequently if events or circumstances arise which indicate that goodwill may be impaired. For instance, a decrease in Quanta’s market capitalization below book value, a significant change in business climate or loss of a significant customer, as well as the qualitative indicators referenced above, may trigger the need for interim impairment testing of goodwill for one or all of its reporting units. The first step of the two-step fair value-based test involves comparing the fair value of each of Quanta’s reporting units with its carrying value, including goodwill. If the carrying value of the reporting unit exceeds its fair value, the second step is performed. The second step compares the carrying amount of the reporting unit’s goodwill to the implied fair value of its goodwill. If the implied fair value of goodwill is less than the carrying amount, an impairment loss would be recorded as a reduction to goodwill with a corresponding charge to operating expense. Quanta determines the fair value of its reporting units using a weighted combination of the discounted cash flow, market multiple and market capitalization valuation approaches, with heavier weighting on the discounted cash flow method, as in management’s opinion, this method currently results in the most accurate calculation of a reporting unit’s fair value. Determining the fair value of a reporting unit requires judgment and the use of significant estimates and assumptions. Such estimates and assumptions include revenue growth rates, operating margins, discount rates, weighted average costs of capital and future market conditions, among others. Quanta believes the estimates and assumptions used in its impairment assessments are reasonable and based on available market information, but variations in any of the assumptions could result in materially different calculations of fair value and determinations of whether or not an impairment is indicated. Under the discounted cash flow method, Quanta determines fair value based on the estimated future cash flows of each reporting unit, discounted to present value using risk-adjusted industry discount rates, which reflect the overall level of inherent risk of a reporting unit and the rate of return an outside investor would expect to earn. Cash flow projections are derived from budgeted amounts and operating forecasts (typically a one-year model) plus an estimate of later period cash flows, all of which are evaluated by management. Subsequent period cash flows are developed for each reporting unit using growth rates that management believes are reasonably likely to occur, along with a terminal value derived from the reporting unit’s earnings before interest, taxes, depreciation and amortization (EBITDA). The EBITDA multiples for each reporting unit are based on trailing twelve-month comparable industry data. Under the market multiple and market capitalization approaches, Quanta determines the estimated fair value of each of its reporting units by applying transaction multiples to each reporting unit’s projected EBITDA and then averaging that estimate with similar historical calculations using either a one, two or three year average. For the market capitalization approach, Quanta adds a reasonable control premium, which is estimated as the premium that would be received in a sale of the reporting unit in an orderly transaction between market participants. The projected cash flows and estimated levels of EBITDA by reporting unit were used to determine fair value under the three approaches discussed herein. The following table presents the significant estimates used by management in determining the fair values of Quanta’s reporting units at December 31, 2015, 2014 and 2013: 2015 2014 2013 Years of cash flows before terminal value 5 5 5 Discount rates 12% to 16% 12% to 14% 12% to 14% EBITDA multiples 5.0 to 6.5 5.0 to 6.0 5.0 to 8.0 Weighting of three approaches: Discounted cash flows 70% 70% 70% Market multiple 15% 15% 15% Market capitalization 15% 15% 15% For recently acquired reporting units, a step one impairment test may indicate an implied fair value that is substantially similar to the reporting unit’s carrying value. Such similarities in value are generally an indication that management’s estimates of future cash flows associated with the recently acquired reporting unit remain relatively consistent with the assumptions that were used to derive its initial fair value. During the fourth quarter of 2015, a two-step fair-value based goodwill impairment analysis was performed for each of Quanta’s reporting units, and no reporting units were evaluated solely on a qualitative basis. Step one of the analysis indicated that the implied fair value of each of Quanta’s reporting units, other than recently acquired reporting units and two other reporting units described below, was substantially in excess of its carrying value. After performing step two of the analysis, management concluded that goodwill was impaired at two reporting units in Quanta’s Oil and Gas Infrastructure Services Division. Accordingly, during the fourth quarter of 2015, Quanta recorded a $39.8 million non-cash charge for the impairment of goodwill which primarily resulted from lower forecasted oil and gas services revenues for its Gulf of Mexico operations and certain operations in Australia, due to the extended low commodity price environment. As discussed generally above, when evaluating the 2015 step one impairment test results, management considered many factors in determining whether or not an impairment of goodwill for any reporting unit was reasonably likely to occur in future periods, including future market conditions and the economic environment in which Quanta’s reporting units were operating. Additionally, management considered the sensitivity of its fair value estimates to changes in certain valuation assumptions. After giving consideration to a 10% decrease in the fair value of each of Quanta’s reporting units, the results of the assessment at December 31, 2015 did not change. However, circumstances such as market declines, unfavorable economic conditions, the loss of a major customer or other factors could increase the risk of impairment of goodwill in future periods. If an operating unit experiences prolonged periods of declining revenues, operating margins or both, it may be at risk of failing step one of the goodwill impairment test. Certain operating units have experienced declines over the short-term due to challenging macroeconomic conditions in certain geographic areas, the decline in oil prices which has impacted customer spending, and delays due to regulatory and permitting issues. Quanta will continue to monitor these conditions and others to determine if it is necessary to perform step two of the fair-value based impairment test for one or more operating units. The goodwill analysis performed for each reporting unit was based on estimates and comparisons obtained from the electric power and oil and gas industries. Quanta assigned a higher weighting to the discounted cash flow approach in all periods to reflect increased expectations of market value being determined from a “held and used” model. As stated previously, cash flows are derived from budgeted amounts and operating forecasts that have been evaluated by management. In connection with the 2015 assessment, projected annual growth rates by reporting unit varied widely with ranges from (28%) to 54%. Quanta’s intangible assets include customer relationships, backlog, trade names, non-compete agreements, patented rights and developed technology, all subject to amortization. The value of customer relationships is estimated as of the date a business is acquired based on the value-in-use concept utilizing the income approach, specifically the excess earnings method. The excess earnings analysis consists of discounting to present value the projected cash flows attributable to the customer relationships, with consideration given to customer contract renewals and estimated customer attrition rates, the importance or lack thereof of existing customer relationships to Quanta’s business plan, income taxes and required rates of return. Quanta values backlog for acquired businesses as of the acquisition date based upon the contractual nature of the backlog within each service line, using the income approach to discount back to present value the cash flows attributable to the backlog. The value of trade names is estimated using the relief-from-royalty method of the income approach. This approach is based on the assumption that in lieu of ownership, a company would be willing to pay a royalty in order to exploit the related benefits of this intangible asset. Quanta amortizes intangible assets based upon the estimated consumption of the economic benefits of each intangible asset, or on a straight-line basis if the pattern of economic benefits consumption cannot otherwise be reliably estimated. Intangible assets subject to amortization are reviewed for impairment and are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. For instance, a significant change in business climate or a loss of a significant customer, among other things, may trigger the need for interim impairment testing of intangible assets. An impairment loss would be recognized if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its fair value. During the fourth quarter of 2015, Quanta recorded an impairment charge of $12.1 million related to customer relationships, trade names and non-compete agreement intangible assets. These intangible asset impairments primarily resulted from lower forecasted oil and gas services revenues for Quanta’s Gulf of Mexico operations and certain operations in Australia, due to the extended low commodity price environment. The two reporting units impacted are in Quanta’s Oil and Gas Infrastructure Services Division. Investments in Affiliates and Other Entities In the normal course of business, Quanta enters into various types of investment arrangements, each having unique terms and conditions. These investments may include equity interests held by Quanta in business entities, including general or limited partnerships, contractual joint ventures, or other forms of equity or profit participation. These investments may also include Quanta’s participation in different financing structures such as the extension of loans to project specific entities, the acquisition of convertible notes issued by project specific entities, or other strategic financing arrangements. Quanta determines whether such investments involve a variable interest entity (VIE) based on the characteristics of the subject entity. If the entity is determined to be a VIE, then management determines if Quanta is the primary beneficiary of the entity and whether or not consolidation of the VIE is required. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the activities of a VIE that most significantly affect the VIE’s economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, in either case that could potentially be significant to the VIE. When Quanta is deemed to be the primary beneficiary, the VIE is consolidated and the other party’s equity interest in the VIE is accounted for as a non-controlling interest. In cases where Quanta determines that it has an undivided interest in the assets, liabilities, revenues and profits of an unincorporated VIE (e.g., a general partnership interest), such amounts are consolidated on a basis proportional to Quanta’s ownership interest in the unincorporated entity. Investments in entities of which Quanta is not the primary beneficiary, but over which Quanta has the ability to exercise significant influence, are accounted for using the equity method of accounting. Quanta’s share of net income or losses from unconsolidated equity investments is included in equity in earnings (losses) of unconsolidated affiliates in the consolidated statements of operations when applicable. Equity investments are reviewed for impairment by assessing whether any decline in the fair value of the investment below the carrying value is other than temporary. In making this determination, factors such as the ability to recover the carrying amount of the investment and the inability of the investee to sustain an earnings capacity are evaluated in determining whether a loss in value should be recognized. Any impairment losses related to investments would be recognized in other expense. Equity method investments are carried at original cost and are included in other assets, net in the consolidated balance sheet and are adjusted for Quanta’s proportionate share of the investees’ income, losses and distributions. On December 6, 2013, Quanta sold all of its equity ownership interest in Howard Midstream Energy Partners, LLC (HEP) for proceeds of approximately $220.9 million, which resulted in a pre-tax gain of approximately $112.7 million. HEP is engaged in the business of owning, operating and constructing midstream plant and pipeline assets in the oil and gas industry. Quanta held an equity ownership interest of approximately 31% in HEP. Revenue Recognition Through its Electric Power Infrastructure Services and Oil and Gas Infrastructure Services segments, Quanta designs, installs and maintains networks for customers in the electric power and oil and gas industries. These services may be provided pursuant to master service agreements, repair and maintenance contracts and fixed price and non-fixed price installation contracts. Pricing under these contracts may be competitive unit price, cost-plus/hourly (or time and materials basis) or fixed price (or lump sum basis), and the final terms and prices of these contracts are frequently negotiated with the customer. Under unit-based contracts, the utilization of an output-based measurement is appropriate for revenue recognition. Under these contracts, Quanta recognizes revenue as units are completed based on pricing established between Quanta and the customer for each unit of delivery, which best reflects the pattern in which the obligation to the customer is fulfilled. Under cost-plus/hourly and time and materials type contracts, Quanta recognizes revenue on an input basis, as labor hours are incurred and services are performed. Revenues from fixed price contracts are recognized using the percentage-of-completion method, measured by the percentage of costs incurred to date to total estimated costs for each contract. These contracts provide for a fixed amount of revenues for the entire project. Such contracts provide that the customer accept completion of progress to date and compensate Quanta for services rendered, which may be measured in terms of units installed, hours expended or some other measure of progress. Contract costs include all direct materials, labor and subcontract costs and those indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and depreciation costs. Much of the material associated with Quanta’s work is owner-furnished and is therefore not included in contract revenues and costs. The cost estimation process is based on professional knowledge and experience of Quanta’s engineers, project managers and financial professionals. Changes in job performance, job conditions and final contract settlements are factors that influence management’s assessment of total contract value and the total estimated costs to complete those contracts and therefore, Quanta’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. These factors are routinely evaluated on a project by project basis throughout the project term, and the impact of corresponding revisions in management’s estimates of contract value, contract cost and contract profit are recorded as necessary in the period in which the revisions are determined. 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. Quanta’s operating results for the years ended December 31, 2015 and 2014 were impacted by less than 5% as a result of changes in contract estimates related to projects that were in progress at December 31, 2014 and 2013. The current asset “Costs and estimated earnings in excess of billings on uncompleted contracts” represents revenues recognized in excess of amounts billed for fixed price contracts. The current liability “Billings in excess of costs and estimated earnings on uncompleted contracts” represents billings in excess of revenues recognized for fixed price contracts. Quanta may incur costs subject to change orders, whether approved or unapproved by the customer, and/or claims related to certain contracts. Quanta determines the probability that such costs will be recovered based upon evidence such as past practices with the customer, specific discussions or preliminary negotiations with the customer or verbal approvals. Quanta treats items as a cost of contract performance in the period incurred if it is not probable that the costs will be recovered or will recognize revenue if it is probable that the contract price will be adjusted and can be reliably estimated. As of December 31, 2015 and 2014, Quanta had approximately $137.2 million and $106.8 million of change orders and/or claims that had been included as contract price adjustments on certain contracts which were in the process of being negotiated in the normal course of business. These aggregate contract price adjustments represent management’s best estimate of additional contract revenues which have been earned and which management believes are probable of collection. The amounts ultimately realized by Quanta upon final acceptance by its customers could be higher or lower than such estimated amounts. Income Taxes Quanta follows the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recorded for future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the underlying assets or liabilities are recovered or settled. Quanta regularly evaluates valuation allowances established for deferred tax assets for which future realization is uncertain. The estimation of required valuation allowances includes estimates of future taxable income. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Quanta considers projected future taxable income and tax planning strategies in making this assessment. If actual future taxable income differs from these estimates, Quanta may not realize deferred tax assets to the extent estimated. Quanta records reserves for income taxes related to certain tax positions in those instances where Quanta considers it more likely than not that additional taxes may be due in excess of amounts reflected on income tax returns filed. When recording reserves for expected tax conseque

New Accounting Pronouncements

New Accounting Pronouncements	12 Months Ended
	Dec. 31, 2015
Accounting Changes and Error Corrections [Abstract]
New Accounting Pronouncements	3. NEW ACCOUNTING PRONOUNCEMENTS: Adoption of New Accounting Pronouncements In April 2014, the Financial Accounting Standards Board (FASB) issued an update that changes the requirement for reporting discontinued operations. A disposal of a component of an entity or a group of components of an entity is required to be reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results when the entity or group of components of an entity meets the criteria to be classified as held for sale or when it is disposed of by sale or other than by sale. The update also requires additional disclosures about discontinued operations, a disposal of an individually significant component of an entity that does not qualify for discontinued operations presentation in the financial statements, and an entity’s significant continuing involvement with a discontinued operation. Quanta adopted this guidance effective January 1, 2015 and has incorporated the new requirements into its presentation of the disposition of its fiber optic licensing operations as discontinued operations. In November 2015, the FASB issued an update that requires deferred tax assets and liabilities, as well as related valuation allowances, to be classified as non-current in a classified balance sheet. For public business entities, the update is effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early application is permitted as of the beginning of an interim or annual reporting period. Quanta adopted this guidance during the quarter ended December 31, 2015, and the guidance has been applied retrospectively to all periods presented. As a result of adopting this guidance, Quanta recorded a reduction to prepaid expenses and other current assets of $49.2 million, a reduction to other assets, net of $0.2 million, a reduction to accounts payable and accrued expenses of $31.0 million and a reduction to deferred tax liabilities of $18.4 million as of December 31, 2014. Additionally, there was a $9.0 million reduction to current assets of discontinued operations and a corresponding reduction to non-current liabilities of discontinued operations as of December 31, 2014. There was no impact on results of operations or cash flows as a result of the adoption of this guidance. Accounting Standards Not Yet Adopted In May 2014, the FASB issued an update that supersedes most current revenue recognition guidance as well as some cost recognition guidance. The update requires that an entity recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This update also requires new qualitative and quantitative disclosures about the nature, amount, timing and uncertainty of revenues and cash flows arising from customer contracts, including significant judgments and changes in judgments, information about contract balances and performance obligations, and assets recognized from costs incurred to obtain or fulfill a contract. On July 9, 2015, the FASB affirmed its proposal to defer the effective date until fiscal years beginning on or after December 15, 2017. The guidance can be applied on a full retrospective or modified retrospective basis whereby the entity records a cumulative effect of initially applying this update at the date of initial application. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and is planning to adopt this guidance effective January 1, 2018. In August 2014, the FASB issued guidance to address the diversity in practice in determining when there is substantial doubt about an entity’s ability to continue as a going concern and when and how an entity must disclose certain relevant conditions and events. This update requires an entity to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern for a period of one year after the date that the financial statements are issued (or available to be issued). If such conditions or events exist, an entity should disclose that there is substantial doubt about the entity’s ability to continue as a going concern for a period of one year after the date that the financial statements are issued (or available to be issued), along with the principal conditions or events that raise substantial doubt, management’s evaluation of the significance of those conditions or events in relation to the entity’s ability to meet its obligations and management’s plans that are intended to mitigate those conditions or events. The guidance is effective for annual and interim periods ending after December 15, 2016. This guidance will impact the disclosure and presentation of any substantial doubt by Quanta about its ability to continue as a going concern, if such substantial doubt were to exist. Quanta will adopt this guidance effective January 1, 2017. In February 2015, the FASB issued an update which amends existing consolidation guidance, including amending the guidance related to determining whether an entity is a variable interest entity. The update is effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The guidance may be applied using a modified retrospective approach whereby the entity records a cumulative effect of adoption at the beginning of the fiscal year of initial application. A reporting entity may also apply the amendments on a full retrospective basis. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In April 2015, the FASB issued an update that requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts and premiums. The standard is effective for interim and annual reporting periods beginning after December 15, 2015, although early adoption is permitted. The update is required to be adopted retroactively for all periods presented. In August 2015, the FASB issued another update that states that the Securities Exchange Commission (SEC) staff would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In April 2015, the FASB issued an update that provides guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The standard is effective for interim and annual reporting periods beginning after December 15, 2015. An entity can elect to adopt the amendments either prospectively to all arrangements entered into or materially modified after the effective date or retrospectively. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In July 2015, the FASB issued an update that requires inventory to be measured at the lower of either cost or net realizable value. When evidence exists that the net realizable value of inventory is lower than its cost, the difference will be recognized as a loss in earnings in the period in which it occurs. The update is required to be adopted prospectively and is effective for interim and annual reporting periods beginning after December 15, 2016, although early adoption is permitted. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and will adopt this guidance by January 1, 2017. In September 2015, the FASB issued an update that requires an acquiring company to recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which such adjustments are determined. An acquiring company must record any effect on earnings from changes in depreciation or amortization or other income effects, calculated as if the accounting had been completed at the acquisition date. The acquiring company must also present separately on the face of the income statement or disclose in the notes the amount recorded in current-period earnings that would have been recorded in previous reporting periods if the adjustment had been recognized as of the acquisition date. The standard is effective for interim and annual reporting periods beginning after December 15, 2015. The update is required to be adopted prospectively to adjustments that occur after the effective date with earlier application permitted for financial statements that have not yet been issued. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In January 2016, the FASB issued an update that addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. The new standard is effective for interim and annual periods beginning after December 15, 2017. Early adoption is permitted for financial statements of fiscal years or interim periods that have not been previously issued. Quanta is evaluating the impact of the new standard on its consolidated financial statements and will adopt the new standard by January 1, 2018. In February 2016, the FASB issued an update that requires companies that lease assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those assets. The new standard is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted for financial statements of fiscal years or interim periods that have not been previously issued. Quanta is evaluating the impact of the new standard on its consolidated financial statements and will adopt the new standard by January 1, 2019.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	4. DISCONTINUED OPERATIONS: On August 4, 2015, Quanta completed the sale of its fiber optic licensing operations to Crown Castle for an aggregate purchase price was approximately $1 billion in cash, resulting in estimated after-tax net proceeds of approximately $848 million. In the third quarter of 2015, Quanta recognized a pre-tax gain of approximately $272 million and a corresponding tax expense of approximately $101 million, which resulted in a gain on the sale, net of tax, of approximately $171 million. Quanta has presented the results of operations, financial position, cash flows and disclosures related to its fiber optic licensing operations as discontinued operations in the accompanying consolidated financial statements. The results were previously included in Quanta’s Fiber Optic Licensing and Other segment. Quanta will remain liable for all taxes and insured claims associated with the fiber optic licensing operations arising on or before or outstanding as of August 4, 2015. The following represents a reconciliation of the major classes of line items constituting income from discontinued operations related to Quanta’s fiber optic licensing operations (in thousands): Year Ended December 31, 2015 2014 2013 Major classes of line items constituting pretax income from fiber optic licensing operations: Revenues $ 59,998 $ 104,021 $ 111,265 Expenses: Cost of services (including depreciation) 24,748 39,295 42,745 Selling, general and administrative expenses 12,047 16,561 15,941 Amortization of intangible assets 963 1,650 1,650 Other income (expense) items that are not major 10 3 — Net income before taxes of discontinued operations related to fiber optic licensing operations related to major classes of income before taxes 22,250 46,518 50,929 Pretax gain on the disposal of the fiber optic licensing operations 271,833 — — Total pretax gain on fiber optic licensing operations 294,083 46,518 50,929 Provision for income taxes related to fiber optic licensing operations 103,462 18,401 21,065 Net income from discontinued operations related to fiber optic licensing operations 190,621 28,117 29,864 Net loss from discontinued operations related to telecommunication operations — $ (627 ) $ — Net income from discontinued operations as presented in the statements of operations $ 190,621 $ 27,490 $ 29,864 The following represents a reconciliation of the carrying amounts of major classes of assets and liabilities of fiber optic licensing operations (in thousands): December 31, December 31, Carrying amounts of major classes of assets included as part of fiber optic licensing operations: Current assets: Accounts receivable $ — $ 11,429 Prepaid expenses and other current assets — 2,258 Total current assets of fiber optic licensing operations $ — $ 13,687 Non-current assets: Property and equipment $ — $ 380,554 Other intangible assets, net of accumulated amortization — 17,009 Goodwill — 334,790 Total major classes of non-current assets of fiber optic licensing operations — 732,353 Other non-current assets included in fiber optic licensing operations — 6,709 Total non-current assets of fiber optic licensing operations $ — $ 739,062 Carrying amounts of major classes of liabilities of fiber optic licensing operations: Current liabilities: Accounts payable and accrued expenses $ 15,313 $ 21,091 Total current liabilities of fiber optic licensing operations $ 15,313 $ 21,091 Non-current liabilities: Deferred income taxes $ — $ 57,108 Long-term deferred revenue — 48,231 Total major classes of non-current liabilities of fiber optic licensing operations — 105,339 Other non-current liabilities of fiber optic licensing operations — 193 Total non-current liabilities of fiber optic licensing operations $ — $ 105,532 Additionally, on December 3, 2012, Quanta sold substantially all of its domestic telecommunications infrastructure services operations and related subsidiaries. During the year ended December 31, 2014, legal fees of $1.0 million were accrued related to an ongoing legal matter associated with these discontinued operations. The net of tax impact of these legal fees was $0.6 million. See Legal Proceedings Lorenzo Benton v. Telecom Network Specialists, Inc., et al.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisitions	5. ACQUISITIONS: 2015 Acquisitions During 2015, Quanta acquired 11 companies. The results of eight of the acquired companies are generally included in Quanta’s Electric Power Infrastructure Services segment. These companies include a foundation services company located in the United States, an electrical contracting company located in the United States, an electrical engineering company located in Australia, a powerline construction company located in the United States, an engineering company located in Canada, an engineering, procurement and construction services company based in the United States, an underground construction contracting company located in Canada, and a supplier and material procurement specialist for the power and utility industry in Canada. The results of the remaining three acquired companies are generally included in Quanta’s Oil and Gas Infrastructure Services segment. These companies include a company that services above-ground storage tanks in the United States, an underground utility distribution contractor that provides services to gas and electric utilities in Canada, and a company that specializes in the engineering, procurement, construction, and commissioning of compression and surface facilities for the high pressure gas industry in Australia. The aggregate consideration for these acquisitions consisted of approximately $110.4 million paid or payable in cash, subject to net working capital adjustments, 461,037 shares of Quanta common stock valued on the settlement dates of the acquisitions at approximately $10.1 million, and $1.0 million in contingent consideration. As these transactions were effective during 2015, the results have been included in Quanta’s consolidated financial statements beginning on the respective dates of acquisition. These acquisitions should enable Quanta to further enhance its electric power and oil and gas infrastructure service offerings in the United States, Canada and Australia. Quanta is in the process of finalizing its assessments of the fair values of the acquired assets and assumed liabilities related to businesses acquired subsequent to December 31, 2014, and further adjustments to the purchase price allocations may occur. Quanta expects to complete the purchase accounting process as soon as practicable but no later than one year from the respective acquisition dates with possible updates primarily related certain tax estimates. The aggregate purchase consideration related to 2015 acquisitions was preliminarily allocated to acquired assets and assumed liabilities, which resulted in a preliminary allocation of approximately $44.7 million of net tangible assets, $51.9 million of goodwill and $25.0 million of other intangible assets. 2014 Acquisitions During 2014, Quanta completed nine acquisitions, which enabled Quanta to further enhance its electric power and oil and gas infrastructure service offerings in the United States and Canada and expand its capabilities in Australia to include electric power infrastructure service offerings. These acquisitions included four electric power infrastructure services companies located in Canada; two oil and gas infrastructure services businesses located in Canada; an electric power infrastructure services company located in Australia; a U.S. based general engineering and construction company specializing in hydrant fueling, waterfront and utility construction for the U.S. Department of Defense that is generally included in Quanta’s Oil and Gas Infrastructure Services segment; and a geotechnical and geological engineering services company based in the United States that is generally included in Quanta’s Electric Power Infrastructure Services segment. The aggregate consideration paid for these acquisitions consisted of approximately $279.5 million in cash, 686,382 shares of Quanta common stock and 3,825,971 exchangeable shares of Canadian subsidiaries of Quanta that are exchangeable on a one-for-one basis for Quanta common stock. In addition, Quanta issued one share of Series G preferred stock associated with 899,858 of the exchangeable shares. The aggregate value of the securities issued related to 2014 acquisitions on the respective closing or settlement dates of the acquisitions, totaled approximately $134.5 million. As these transactions were effective during 2014, the results of each acquired company have been included in Quanta’s consolidated financial statements beginning on the respective dates of acquisition. For additional information on the exchangeable shares and preferred stock, see Exchangeable Shares and Series F and Series G Preferred Stock 2013 Acquisitions During 2013, Quanta acquired six businesses, which enabled Quanta to further enhance its electric power infrastructure and oil and gas infrastructure service offerings in the United States, Canada and Australia. The aggregate consideration paid for these acquisitions consisted of approximately $341.1 million in cash and 3,547,482 shares of Quanta common stock valued, as of the respective dates of issuance, at approximately $88.9 million. The results for each company have been included in Quanta’s consolidated financial statements beginning on the respective dates of acquisition. 2015, 2014 and 2013 Acquisitions The following table summarizes the aggregate consideration paid or payable as of December 31, 2015 for the 2015 and 2014 acquisitions and presents the allocation of these amounts to the net tangible and identifiable intangible assets based on their estimated fair values as of the respective acquisition dates. This allocation requires a significant use of estimates and is based on information that was available to management at the time these consolidated financial statements were prepared (in thousands). 2015 2014 Consideration: Value of Quanta common stock and exchangeable shares issued $ 10,127 $ 134,538 Cash paid or payable 110,428 279,533 Contingent consideration 1,001 — Fair value of total consideration transferred or estimated to be transferred $ 121,556 $ 414,071 Current assets $ 35,188 $ 172,121 Property and equipment 44,140 159,186 Other assets 4 3,501 Identifiable intangible assets 24,987 96,302 Current liabilities (24,633 ) (145,646 ) Deferred tax liabilities, net (5,131 ) (32,856 ) Other long-term liabilities (5,606 ) (4,926 ) Non-controlling interests 747 — Total identifiable net assets 69,696 247,682 Goodwill 51,860 166,389 $ 121,556 $ 414,071 The fair value of current assets acquired in 2015 included accounts receivable with a fair value of $20.6 million. The fair value of current assets acquired in 2014 included accounts receivable with a fair value of $117.2 million. Goodwill represents the excess of the purchase price over the net amount of the fair values assigned to assets acquired and liabilities assumed. The 2015, 2014 and 2013 acquisitions strategically expanded Quanta’s Canadian, Australian and domestic electric power and oil and gas service offerings, which Quanta believes contributes to the recognition of the goodwill. In connection with the 2015 acquisitions, goodwill of $31.2 million was recorded for the businesses acquired that were included within Quanta’s Electric Power Infrastructure Services Division and $20.6 million was recorded for businesses included within Quanta’s Oil and Gas Infrastructure Services Division on the dates of acquisition. In connection with the 2014 acquisitions, goodwill of $72.3 million was recorded for the businesses included within Quanta’s Electric Power Infrastructure Services Division and $94.1 million was recorded for businesses included within Quanta’s Oil and Gas Infrastructure Services Division based on fair market values of assets and liabilities on the dates of acquisition. In connection with the 2013 acquisitions, goodwill of $112.5 million was recorded for businesses included within Quanta’s Electric Power Infrastructure Services Division and $143.3 million was recorded for the business included within Quanta’s Oil and Gas Infrastructure Services Division on the dates of acquisition. Goodwill of approximately $33.9 million and $43.5 million is expected to be deductible for income tax purposes related to the businesses acquired in 2015 and 2014. The following table summarizes the estimated fair values of identifiable intangible assets and the related weighted average amortization periods by type as of the respective acquisition dates for the 2015 acquisitions (in thousands, except for weighted average amortization periods, which are in years). Estimated Weighted Average Customer relationships $ 16,257 13.7 Backlog 2,552 1.3 Trade names 4,002 8.8 Non-compete agreements 2,176 5.0 Total intangible assets subject to amortization acquired in 2015 acquisitions $ 24,987 10.9 The unaudited supplemental pro forma results of operations have been provided for illustrative purposes only and do not purport to be indicative of the actual results that would have been achieved by the combined companies for the periods presented or that may be achieved by the combined companies in the future. Future results may vary significantly from the results reflected in the following pro forma financial information because of future events and transactions, as well as other factors (in thousands, except per share amounts): Year Ended December 31, 2015 2014 2013 Revenues $ 7,635,932 $ 8,476,584 $ 7,629,310 Gross profit $ 939,452 $ 1,248,827 $ 1,185,691 Selling, general and administrative expenses $ 600,057 $ 745,321 $ 563,877 Amortization of intangible assets $ 36,479 $ 47,777 $ 50,755 Net income from continuing operations $ 135,467 $ 303,772 $ 451,399 Net income from continuing operations attributable to common stock $ 124,550 $ 285,404 $ 432,011 Earnings per share from continuing operations attributable to common stock — basic and diluted $ 0.64 $ 1.28 $ 1.95 The pro forma combined results of operations for the years ended December 31, 2015 and 2014 have been prepared by adjusting the historical results of Quanta to include the historical results of the 2015 acquisitions as if they occurred January 1, 2014. The pro forma combined results of operations for the year ended December 31, 2014 have also been prepared by adjusting the historical results of Quanta to include the historical results of the 2014 acquisitions as if they occurred January 1, 2013. The pro forma combined results of operations for the year ended December 31, 2013 have been prepared by adjusting the historical results of Quanta to include the historical results of the 2014 acquisitions as if they occurred January 1, 2013 and the historical results of the 2013 acquisitions as if it occurred January 1, 2012. These pro forma combined historical results were also adjusted for the following: a reduction of interest expense as a result of the repayment of outstanding indebtedness of the acquired businesses, a reduction of interest income as a result of the cash consideration paid net of cash received, an increase in amortization expense due to the incremental intangible assets recorded related to the 2015, 2014 and 2013 acquisitions, an increase or decrease in depreciation expense within cost of services related to the net impact of adjusting acquired property and equipment to the acquisition date fair value and conforming depreciable lives with Quanta’s accounting policies, an increase in the number of outstanding shares of Quanta common stock and exchangeable shares and certain reclassifications to conform the acquired companies’ presentation to Quanta’s accounting policies. The pro forma results of operations do not include any adjustments to eliminate the impact of acquisition related costs or any cost savings or other synergies that may result from the 2015, 2014 and 2013 acquisitions. As noted above, the pro forma results of operations do not purport to be indicative of the actual results that would have been achieved by the combined company for the periods presented or that may be achieved by the combined company in the future. Revenues of approximately $104.6 million and income from continuing operations before income taxes of approximately $0.3 million, which included $3.6 million of acquisition costs, were included in Quanta’s consolidated results of operations for the year ended December 31, 2015 related to the 11 acquisitions in 2015 following their respective dates of acquisition. Revenues of approximately $314.1 million and income from continuing operations before income taxes of approximately $3.4 million, which included $11.6 million of acquisition costs, were included in Quanta’s consolidated results of operations for the year ended December 31, 2014 related to the nine 2014 acquisitions following their respective dates of acquisition. Additionally, revenues of approximately $251.3 million and income from continuing operations before income taxes of approximately $18.2 million were included in Quanta’s consolidated results of operations for the year ended December 31, 2013 related to the six 2013 acquisitions following their respective dates of acquisition.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	6. GOODWILL AND OTHER INTANGIBLE ASSETS: A summary of changes in Quanta’s goodwill is as follows (in thousands): Electric Power Infrastructure Oil and Gas Services Division Total Goodwill balance at December 31, 2013 $ 1,168,084 $ 277,843 $ 1,445,927 Goodwill acquired during 2014 71,517 102,968 174,485 Foreign currency translation adjustments (16,377 ) (7,340 ) (23,717 ) Goodwill balance at December 31, 2014 1,223,224 373,471 1,596,695 Goodwill acquired during 2015 31,224 20,636 51,860 Purchase price allocation adjustments 750 (8,867 ) (8,117 ) Goodwill impaired during 2015 — (39,826 ) (39,826 ) Foreign currency translation adjustments (28,953 ) (19,001 ) (47,954 ) Balance at December 31, 2015: Goodwill $ 1,226,245 $ 366,306 $ 1,592,551 Accumulated impairment — (39,893 ) (39,893 ) $ 1,226,245 $ 326,413 $ 1,552,658 The purchase price allocation adjustments recorded in the year ended December 31, 2015 resulted primarily from net working capital adjustments and changes in tax estimates. The goodwill impairment in the year ended December 31, 2015 primarily resulted from lower forecasted oil and gas services revenues for Quanta’s Gulf of Mexico operations and certain operations in Australia, due to the extended low commodity price environment. The two reporting units impacted are in Quanta’s Oil and Gas Infrastructure Services Division. Also, as described in Note 2, Quanta’s operating units are organized into one of Quanta’s two internal divisions and, accordingly, the goodwill associated with its operating units has been aggregated on a divisional basis and reported in the table above. These divisions are closely aligned with Quanta’s reportable segments and are based on the predominant type of work performed by each operating unit. From time to time, operating units may be reorganized between these internal divisions as business environments evolve. Quanta’s intangible assets subject to amortization and the remaining weighted average amortization periods related to such assets were as follows (in thousands except for weighted average amortization periods, which are in years): As of December 31, 2015 As of December 31, 2014 As of December 31, 2015 Intangible Assets Accumulated Amortization Intangible Assets, Net Intangible Assets Accumulated Amortization Intangible Assets, Net Remaining Customer relationships $ 236,731 $ (90,840 ) $ 145,891 $ 235,851 $ (63,764 ) $ 172,087 9.7 Backlog 130,818 (126,954 ) 3,864 133,704 (122,265 ) 11,439 0.7 Trade names 51,192 (9,525 ) 41,667 49,664 (6,278 ) 43,386 18.6 Non-compete agreements 28,560 (23,507 ) 5,053 27,659 (21,365 ) 6,294 3.5 Patented rights and developed technology 22,447 (13,848 ) 8,599 22,073 (11,695 ) 10,378 4.0 Total intangible assets subject to amortization $ 469,748 $ (264,674 ) $ 205,074 $ 468,951 $ (225,367 ) $ 243,584 10.9 Amortization expense for intangible assets was $34.8 million, $34.3 million and $25.9 million for the years ended December 31, 2015, 2014 and 2013, respectively. Additionally, during the year ended December 31, 2015, Quanta recorded an impairment charge of $12.1 million related to customer relationships, trade names and non-compete agreement intangible assets. These intangible asset impairments primarily resulted from lower forecasted oil and gas services revenues for Quanta’s Gulf of Mexico operations and certain operations in Australia, due to the extended low commodity price environment. The two reporting units impacted are in Quanta’s Oil and Gas Infrastructure Services Division. The impairment charge is reflected in the December 31, 2015 accumulated amortization balances above. The estimated future aggregate amortization expense of intangible assets subject to amortization as of December 31, 2015 is set forth below (in thousands): For the Fiscal Year Ending December 31, 2016 $ 28,172 2017 22,758 2018 22,015 2019 21,219 2020 20,103 Thereafter 90,807 Total $ 205,074

Per Share Information

Per Share Information	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Per Share Information	7. PER SHARE INFORMATION: Basic earnings per share is computed using the weighted average number of common shares outstanding during the period, and diluted earnings per share is computed using the weighted average number of common shares outstanding during the period adjusted for all potentially dilutive common stock equivalents, except in cases where the effect of the common stock equivalent would be antidilutive. The amounts used to compute the basic and diluted earnings per share for the years ended December 31, 2015, 2014 and 2013 are illustrated below (in thousands): Year Ended December 31, 2015 2014 2013 Amounts attributable to common stock: Net income from continuing operations $ 120,286 $ 269,224 $ 372,057 Net income from discontinued operations 190,621 27,490 29,864 Net income attributable to common stock $ 310,907 $ 296,714 $ 401,921 Weighted average shares: Weighted average shares outstanding for basic earnings per share 195,113 219,668 214,929 Effect of dilutive stock options 7 22 49 Weighted average shares outstanding for diluted earnings per share 195,120 219,690 214,978 For purposes of calculating diluted earnings per share, there were no adjustments required to derive Quanta’s net income attributable to common stock. Outstanding exchangeable shares that were issued pursuant to certain of Quanta’s historical acquisitions (as further discussed in Note 11), which are exchangeable on a one-for-one basis with shares of Quanta common stock, have been included in weighted average shares outstanding for basic and diluted earnings per share for the years ended December 31, 2015, 2014 and 2013 for the portion of the respective periods that they were outstanding. However, any additional shares that may be delivered under Quanta’s accelerated share repurchase arrangement entered into on August 7, 2015 (as further described in Note 11) have not been included in the weighted average shares outstanding for basic and diluted earnings per share for the year ended December 31, 2015 because their effect would be anti-dilutive.

Detail of Certain Balance Sheet

Detail of Certain Balance Sheet Accounts	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Detail of Certain Balance Sheet Accounts	8. DETAIL OF CERTAIN BALANCE SHEET ACCOUNTS: Activity in Quanta’s current and long-term allowance for doubtful accounts consisted of the following (in thousands): December 31, 2015 2014 Balance at beginning of year $ 6,174 $ 5,215 Charged to bad debt expense and provision for long-term contract receivable 224 103,871 Deductions for uncollectible receivables written off, net of recoveries (1,172 ) (102,912 ) Balance at end of year $ 5,226 $ 6,174 Included in the 2014 amounts charged and written off was the $102.5 million charge to provision for long-term contract receivable and subsequent write-off related to the Sunrise Powerlink project. See Legal Proceedings — Sunrise Powerlink Arbitration Contracts in progress were as follows (in thousands): December 31, 2015 2014 Costs incurred on contracts in progress $ 5,725,078 $ 6,603,351 Estimated earnings, net of estimated losses 756,974 1,111,657 6,482,052 7,715,008 Less — Billings to date (6,563,537 ) (7,675,674 ) $ (81,485 ) $ 39,334 Costs and estimated earnings in excess of billings on uncompleted contracts $ 317,745 $ 290,447 Less — Billings in excess of costs and estimated earnings on uncompleted contracts (399,230 ) (251,113 ) $ (81,485 ) $ 39,334 Property and equipment consisted of the following (in thousands): Estimated Useful Lives in Years December 31, 2015 2014 Land N/A $ 41,428 $ 40,657 Buildings and leasehold improvements 5-30 116,697 93,042 Operating equipment and vehicles 5-25 1,517,630 1,459,409 Office equipment, furniture and fixtures and information technology systems 3-15 137,670 119,529 Construction work in progress N/A 43,806 38,496 1,857,231 1,751,133 Less — Accumulated depreciation and amortization (755,272 ) (651,559 ) Property and equipment, net $ 1,101,959 $ 1,099,574 Accounts payable and accrued expenses consisted of the following (in thousands): December 31, 2015 2014 Accounts payable, trade $ 452,295 $ 477,370 Accrued compensation and related expenses 159,045 164,777 Accrued insurance, current portion 61,327 49,309 Deferred revenues, current portion 8,010 13,082 Income and franchise taxes payable 3,923 20,946 Other accrued expenses 97,534 99,747 $ 782,134 $ 825,231

Debt Obligations

Debt Obligations	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Debt Obligations	9. DEBT OBLIGATIONS: Quanta’s long-term debt obligations consisted of the following (in thousands): December 31, 2015 2014 Borrowings under credit facility $ 466,850 $ 68,793 Other long-term debt, interest rates ranging from 3.4% to 4.3% 5,401 6,370 Capital leases, interest rates ranging from 2.5% to 6.2% 5,351 1,146 Total long-term debt obligations 477,602 76,309 Less — Current maturities of long-term debt 2,238 3,820 Total long-term debt obligations, net of current maturities $ 475,364 $ 72,489 Quanta’s current maturities of long-term debt and short-term borrowings consisted of the following (in thousands): December 31, 2015 2014 Short-term borrowings $ 4,829 $ 5,056 Current maturities of long-term debt 2,238 3,820 Current maturities of long-term debt and short-term borrowings $ 7,067 $ 8,876 Credit Facility On December 18, 2015, Quanta entered into an amended and restated credit agreement with various lenders that provides for a $1.81 billion senior secured revolving credit facility maturing on December 18, 2020. The entire amount available under the facility may be used by Quanta for revolving loans and letters of credit in U.S. dollars and certain alternative currencies. Up to $600.0 million of the facility may be used by certain subsidiaries of Quanta for revolving loans and letters of credit in certain alternative currencies. Up to $100.0 million of the facility may be used for swing line loans in U.S. dollars, up to $50.0 million of the facility may be used for swing line loans in Canadian dollars and up to $30.0 million of the facility may be used for swing line loans in Australian dollars. In addition, subject to the conditions specified in the credit agreement, Quanta has the option to increase the revolving commitments by up to $400.0 million from time to time upon receipt of additional commitments from new or existing lenders. Borrowings under the credit agreement are to be used to refinance existing indebtedness and for working capital, capital expenditures and other general corporate purposes. As of December 31, 2015, Quanta had approximately $307.0 million of outstanding letters of credit and bank guarantees, $220.0 million of which was denominated in U.S. dollars and $87.0 million of which was denominated in Australian or Canadian dollars. Quanta also had $466.9 million of outstanding revolving loans under the credit facility, $400.0 million of which was denominated in U.S. dollars and $66.9 million of which was denominated in Canadian dollars. The remaining $1.04 billion was available for revolving loans or issuing new letters of credit or bank guarantees. Information on borrowings under Quanta’s credit facility and the applicable interest rates during the years ended December 31, 2015 and 2014 is as follows (dollars in thousands): Year Ended December 31, 2015 2014 2013 Maximum amount outstanding during the period $ 606,753 $ 130,856 $ 161,920 Average daily amount outstanding under the credit facility $ 258,815 $ 29,814 $ 14,482 Weighted-average interest rate 1.79 % 2.71 % 2.12 % Under the current credit agreement, amounts borrowed in U.S. dollars bear interest, at Quanta’s option, at a rate equal to either (i) the Eurocurrency Rate (as defined in the credit agreement) plus 1.125% to 2.125%, as determined based on Quanta’s Consolidated Leverage Ratio (as described below), or (ii) the Base Rate (as described below) plus 0.125% to 1.125%, as determined based on Quanta’s Consolidated Leverage Ratio. Amounts borrowed as revolving loans under the credit agreement in any currency other than U.S. dollars bear interest at a rate equal to the Eurocurrency Rate plus 1.125% to 2.125%, as determined based on Quanta’s Consolidated Leverage Ratio. Standby letters of credit issued under the credit agreement are subject to a letter of credit fee of 1.125% to 2.125%, based on Quanta’s Consolidated Leverage Ratio, and Performance Letters of Credit (as defined in the credit agreement) issued under the credit agreement in support of certain contractual obligations are subject to a letter of credit fee of 0.675% to 1.275%, based on Quanta’s Consolidated Leverage Ratio. Quanta is also subject to a commitment fee of 0.20% to 0.40%, based on its Consolidated Leverage Ratio, on any unused availability under the credit agreement. The Consolidated Leverage Ratio is the ratio of Quanta’s Consolidated Funded Indebtedness to Consolidated EBITDA (as those terms are defined in the credit agreement). For purposes of calculating Quanta’s Consolidated Leverage Ratio, Consolidated Funded Indebtedness is reduced by available cash and Cash Equivalents (as defined in the credit agreement) in excess of $25.0 million. The Base Rate equals the highest of (i) the Federal Funds Rate (as defined in the credit agreement) plus 0.5%, (ii) the prime rate publicly announced by Bank of America, N.A. and (iii) the Eurocurrency Rate plus 1.00%. Subject to certain exceptions, the credit agreement is secured by substantially all the assets of Quanta and Quanta’s wholly owned U.S. subsidiaries and by a pledge of all of the capital stock of Quanta’s wholly owned U.S. subsidiaries and 65% of the capital stock of direct foreign subsidiaries of Quanta’s wholly owned U.S. subsidiaries. Quanta’s wholly owned U.S. subsidiaries also guarantee the repayment of all amounts due under the credit agreement. Subject to certain conditions, all collateral will automatically be released from the liens at any time Quanta maintains an Investment Grade Rating (defined in the credit agreement as two of the following three conditions being met: (i) a corporate credit rating that is BBB- or higher by Standard & Poor’s Rating Services, (ii) a corporate family rating that is Baa3 or higher by Moody’s Investors Services, Inc. or (iii) a corporate credit rating that is BBB- or higher by Fitch Ratings, Inc.). The credit agreement contains certain covenants, including a maximum Consolidated Leverage Ratio and a minimum Consolidated Interest Coverage Ratio (as defined in the credit agreement). The credit agreement also limits certain acquisitions, mergers and consolidations, indebtedness, asset sales and prepayments of indebtedness and, subject to certain exceptions, prohibits liens on Quanta’s assets. The credit agreement allows cash payments for dividends and stock repurchases subject to compliance with the following requirements (after giving effect to the dividend or stock repurchase): (i) no default or event of default under the credit agreement; (ii) continued compliance with the financial covenants in the credit agreement; and (iii) at least $100.0 million of availability under the credit agreement and/or cash and cash equivalents on hand. As of December 31, 2015, Quanta was in compliance with all of the covenants in the credit agreement. The credit agreement provides for customary events of default and contains cross-default provisions with Quanta’s underwriting, continuing indemnity and security agreement with its sureties and all of Quanta’s other debt instruments exceeding $100.0 million in borrowings or availability. If an Event of Default (as defined in the credit agreement) occurs and is continuing, on the terms and subject to the conditions set forth in the credit agreement, the lenders may declare all amounts outstanding and accrued and unpaid interest immediately due and payable, require that Quanta provide cash collateral for all outstanding letter of credit obligations, terminate the commitments under the credit agreement, and foreclose on the collateral. Prior to the recent amendment and restatement of our credit agreement and after April 1, 2014, amounts borrowed bore interest at the same rates as above, and Quanta was subject to the same commitment fees as above. Prior to April 1, 2014, amounts borrowed in U.S. dollars bore interest, at Quanta’s option, at a rate equal to either (i) the Eurocurrency Rate plus 1.25%, or (ii) the Base Rate plus 0.25%, and amounts borrowed as revolving loans in any currency other than U.S. dollars bore interest at a rate equal to the Eurocurrency Rate plus 1.25%. Prior to April 1, 2014, standby letters of credit issued under the credit agreement were also subject to a letter of credit fee of 1.25%, Performance Letters of Credit issued in support of certain contractual obligations were subject to a letter of credit fee of 0.75%, and Quanta was also subject to a commitment fee of 0.20% on any unused availability under the credit agreement. Prior to amendment and restatement of the credit agreement on October 30, 2013, Quanta’s credit agreement provided for a $700.0 million senior secured revolving credit facility. Borrowings were used to refinance existing indebtedness and for working capital, capital expenditures and other general corporate purposes. Amounts borrowed in U.S. dollars bore interest, at Quanta’s option, at a rate equal to either (a) the Eurocurrency Rate (as defined in the credit agreement) plus 1.25% to 2.50%, as determined based on Quanta’s Consolidated Leverage Ratio (as described below), plus, if applicable, any Mandatory Cost (as defined in the credit agreement) required to compensate lenders for the cost of compliance with certain European regulatory requirements, or (b) the Base Rate (as described below) plus 0.25% to 1.50%, as determined based on Quanta’s Consolidated Leverage Ratio. Amounts borrowed in any currency other than U.S. dollars bore interest at a rate equal to the Eurocurrency Rate plus 1.25% to 2.50%, as determined based on Quanta’s Consolidated Leverage Ratio, plus, if applicable, any Mandatory Cost. Standby letters of credit issued under the credit agreement were subject to a letter of credit fee of 1.25% to 2.50%, based on Quanta’s Consolidated Leverage Ratio, and Performance Letters of Credit (as defined in the credit agreement) issued under the credit agreement in support of certain contractual obligations were subject to a letter of credit fee of 0.75% to 1.50%, based on Quanta’s Consolidated Leverage Ratio. Quanta was also subject to a commitment fee of 0.20% to 0.45%, based on Quanta’s Consolidated Leverage Ratio, on any unused availability under the credit agreement. The Consolidated Leverage Ratio was the ratio of Quanta’s total funded debt to Consolidated EBITDA (as those terms are defined in the credit agreement). For purposes of calculating both the Consolidated Leverage Ratio and the maximum senior debt to Consolidated EBITDA ratio discussed above, total funded debt and total senior debt were reduced by all unrestricted cash and Cash Equivalents (as defined in the credit agreement) held by Quanta in excess of $25.0 million. The Base Rate equaled the highest of (i) the Federal Funds Rate (as defined in the credit agreement) plus 0.5%, (ii) the prime rate publicly announced by Bank of America, N.A. and (iii) the Eurocurrency Rate plus 1.00%.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	10. INCOME TAXES: The components of income (loss) from continuing operations before income taxes were as follows (in thousands): Year Ended December 31, 2015 2014 2013 Income (loss) from continuing operations before income taxes: Domestic $ 244,955 $ 263,357 $ 472,816 Foreign (16,280 ) 163,242 115,504 Total $ 228,675 $ 426,599 $ 588,320 The components of the provision for income taxes for continuing operations were as follows (in thousands): Year Ended December 31, 2015 2014 2013 Current: Federal $ 85,830 $ 67,430 $ 164,397 State 9,783 8,693 20,998 Foreign 21,262 39,978 37,193 Total current tax provision 116,875 116,101 222,588 Deferred: Federal (5,247 ) 11,507 (22,611 ) State 917 2,232 (2,540 ) Foreign (15,073 ) 9,167 (562 ) Total deferred tax provision (benefit) (19,403 ) 22,906 (25,713 ) Total provision for income taxes from continuing operations $ 97,472 $ 139,007 $ 196,875 The actual income tax provision differed from the income tax provision computed by applying the U.S. federal statutory corporate rate to income from continuing operations before provision for income taxes as follows (in thousands): Year Ended December 31, 2015 2014 2013 Provision at the statutory rate $ 80,036 $ 149,697 $ 205,912 Increases (decreases) resulting from — State taxes 7,241 7,890 11,201 Foreign taxes 1,239 (13,059 ) (9,994 ) Contingency reserves, net 4,438 (650 ) (3,385 ) Production activity deduction (6,871 ) (6,033 ) (10,247 ) Employee per diems, meals and entertainment 8,727 9,817 7,888 Taxes on unincorporated joint ventures (3,838 ) (6,429 ) (6,786 ) Asset impairments 7,047 — — Other (547 ) (2,226 ) 2,286 Total provision for income taxes from continuing operations $ 97,472 $ 139,007 $ 196,875 Deferred income taxes result from temporary differences in the recognition of income and expenses for financial reporting purposes and tax purposes. The tax effects of these temporary differences, representing deferred tax assets and liabilities, result principally from the following (in thousands): December 31, 2015 2014 Deferred income tax liabilities: Property and equipment $ (189,793 ) $ (185,007 ) Goodwill (69,059 ) (70,832 ) Other intangibles (36,565 ) (48,344 ) Other book/tax accounting method differences (61,095 ) (63,819 ) Total deferred income tax liabilities $ (356,512 ) (368,002 ) Deferred income tax assets: Accruals and reserves 25,070 20,835 Accrued insurance 75,591 64,745 Stock and incentive compensation and pension withdrawal liabilities 52,009 53,155 Net operating loss carryforwards 27,255 19,353 Other 10,894 10,194 Subtotal 190,819 168,282 Valuation allowance (16,141 ) (13,028 ) Total deferred income tax assets 174,678 155,254 Total net deferred income tax liabilities $ (181,834 ) $ (212,748 ) The net deferred income tax assets and liabilities were comprised of the following (in thousands): December 31, 2015 2014 Deferred income taxes: Assets 4,657 3,233 Liabilities (186,491 ) (215,981 ) Total net deferred income tax liabilities $ (181,834 ) $ (212,748 ) The valuation allowance for deferred income tax assets at December 31, 2015, 2014 and 2013 was $16.1 million, $13.0 million and $13.3 million, respectively. These valuation allowances relate to foreign net operating loss carryforwards, state net operating loss carryforwards and foreign tax credit carryforwards. The net change in the total valuation allowance for each of the years ended December 31, 2015, 2014 and 2013 was an increase of $3.1 million, a decrease of $0.3 million and an increase of $6.4 million, respectively. The valuation allowance was established primarily as a result of uncertainty in Quanta’s outlook as to future taxable income in particular tax jurisdictions. Quanta believes it is more likely than not that it will realize the benefit of its deferred tax assets, net of existing valuation allowances. At December 31, 2015, Quanta had state and foreign net operating loss carryforwards, the tax effect of which was approximately $29.8 million. These carryforwards will expire as follows: 2016, $0.1 million; 2017, $1.2 million; 2018, $0.7 million; 2019, $0.7 million; 2020, $0.3 million and $26.8 million thereafter. A valuation allowance of $13.9 million has been recorded against certain foreign and state net operating loss carryforwards. Through December 31, 2015, Quanta has not provided U.S. income taxes on approximately $269.8 million of unremitted foreign earnings. If Quanta was to repatriate cash that is indefinitely reinvested outside the U.S., it could be subject to additional U.S income and foreign withholding taxes. Because of the number and variability of assumptions required, it is not practicable to determine the amount of any additional U.S. tax liability that may result if Quanta decides to no longer indefinitely reinvest foreign earnings outside the U.S. If Quanta’s intentions or U.S. tax laws change in the future, there may be a significant negative impact on the provision for income taxes and cash flows as a result of recording an incremental tax liability, in the period such change occurs. A reconciliation of unrecognized tax benefit balances is as follows (in thousands): December 31, 2015 2014 2013 Balance at beginning of year $ 50,668 $ 48,306 $ 50,555 Additions based on tax positions related to the current year 5,340 9,133 8,984 Additions for tax positions of prior years 292 2,438 — Reductions for tax positions of prior years (132 ) — — Reductions for audit settlements (1,345 ) — — Reductions resulting from a lapse of the applicable statute of limitations periods (282 ) (9,209 ) (11,233 ) Balance at end of year $ 54,541 $ 50,668 $ 48,306 For the year ended December 31, 2015, the $0.3 million reduction was primarily due to the expiration of certain federal and state statute of limitations periods for the 2004 tax year. For the year ended December 31, 2014, the $9.2 million reduction was primarily due to the expiration of certain federal and state statute of limitations periods for the 2010 tax year. For the year ended December 31, 2013, the $11.2 million reduction was primarily due to the expiration of certain federal and state statute of limitations periods for the 2009 tax year. The balances of unrecognized tax benefits, the amount of related interest and penalties and what Quanta believes to be the range of reasonably possible changes in the next 12 months are as follows (in thousands): December 31, 2015 2014 2013 Unrecognized tax benefits $ 54,541 $ 50,668 $ 48,306 Portion that, if recognized, would reduce tax expense and effective tax rate 48,312 42,952 40,029 Accrued interest on unrecognized tax benefits 8,750 6,304 5,766 Accrued penalties on unrecognized tax benefits 673 697 99 Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months $ 0 to $27,485 $ 0 to $10,221 $ 0 to $6,554 Portion that, if recognized, would reduce tax expense and effective tax rate $ 0 to $24,009 $ 0 to $8,484 $ 0 to $4,816 Quanta classifies interest and penalties within the provision for income taxes. Quanta recognized interest expense of $2.4 million, interest expense of $0.5 million and interest income of $0.2 million in the provision for income taxes for the years ended December 31, 2015, 2014 and 2013, respectively. Quanta is currently under examination by the IRS for calendar years 2010, 2011 and 2012, and the federal statute of limitations for examination in all subsequent tax years remains open. Additionally, certain subsidiaries are under examination by various U.S. state, Canadian and other foreign tax authorities for multiple periods. Quanta’s Canadian subsidiaries remain open to examination by the Canada Revenue Agency for tax years 2010 through 2014 as these statute of limitations periods have not yet expired. Quanta does not consider any state in which it does business to be a major tax jurisdiction.

Equity

Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Equity	11. EQUITY: Exchangeable Shares and Series F and Series G Preferred Stock In connection with certain Canadian acquisitions, the former owners of the acquired companies received exchangeable shares of certain Canadian subsidiaries of Quanta, which may be exchanged at the option of the holders for Quanta common stock on a one-for-one basis. The holders of exchangeable shares can make an exchange only once in any calendar quarter and must exchange a minimum of either 50,000 shares or, if less, the total number of remaining exchangeable shares registered in the name of the holder making the request. Additionally, in connection with two of such acquisitions, Quanta issued one share of Quanta Series F preferred stock and one share of Quanta Series G preferred stock (the Preferred Stock) to voting trusts on behalf of the respective holders of the exchangeable shares issued in such acquisitions. Each share of the Preferred Stock provides the holders of such exchangeable shares voting rights in Quanta common stock equivalent to the number of exchangeable shares outstanding at that time. The holders of exchangeable shares associated with the Preferred Stock have rights equivalent to Quanta common stockholders with respect to voting, dividends and other economic rights. The holders of exchangeable shares not associated with the Preferred Stock have rights equivalent to Quanta common stockholders with respect to dividends and other economic rights but do not have voting rights. During 2015 and 2013, 449,929 and 409,110 exchangeable shares associated with the Preferred Stock were exchanged for Quanta common stock. As of December 31, 2015, both shares of the Preferred Stock remained outstanding and 6,876,042 exchangeable shares remained outstanding, of which 3,949,929 were associated with the Preferred Stock. Treasury Stock Under the stock incentive plans described in Note 12, the tax withholding obligations of employees upon vesting of restricted stock awards and RSUs settled in common stock are typically satisfied by Quanta making such tax payments and withholding a number of vested shares having a value on the date of vesting equal to the tax withholding obligation. For the settlement of these employee tax liabilities, Quanta withheld 365,070 shares of Quanta common stock during the year ended December 31, 2015, with a total market value of $10.4 million, 352,558 shares of Quanta common stock during the year ended December 31, 2014 with a total market value of $12.3 million, and 379,566 shares of Quanta common stock during the year ended December 31, 2013 with a total market value of $12.1 million. These shares and the related costs to acquire them were accounted for as adjustments to the balance of treasury stock. Under Delaware corporate law, treasury stock is not counted for quorum purposes or entitled to vote. During the third quarter of 2015, Quanta’s board of directors approved a new stock repurchase program authorizing Quanta to purchase, from time to time through February 28, 2017, up to $1.25 billion of its outstanding common stock (the 2015 Repurchase Program). Repurchases under the 2015 Repurchase Program can be made in open market or privately negotiated transactions, including pursuant to an accelerated share repurchase arrangement, an issuer repurchase plan or otherwise, at management’s discretion, based on market and business conditions, applicable contractual and legal requirements and other factors. The 2015 Repurchase Program does not obligate Quanta to acquire any specific amount of common stock and may be modified or terminated by Quanta’s board of directors at any time at its sole discretion and without notice. On August 7, 2015, Quanta entered into an accelerated share repurchase arrangement (the ASR) to repurchase $750.0 million of its common stock under the 2015 Repurchase Program. Under the terms of the ASR, Quanta paid $750.0 million to JPMorgan Chase Bank, National Association, London Branch (JPMorgan) and initially received 25.7 million shares of its common stock. The fair market value of these 25.7 million shares at the time of delivery was approximately $600.0 million, and the repurchased shares and the related cost to acquire them were accounted for as an adjustment to the balance of treasury stock during the quarter ended September 30, 2015, reducing the weighted-average number of basic and diluted common shares used to calculate Quanta’s earnings per share for the year ended December 31, 2015. The $150.0 million remaining under the ASR was recorded as an adjustment to additional paid-in capital (APIC) during the quarter ended September 30, 2015 and will be reclassified from APIC to treasury stock upon final settlement of the ASR. The final number of shares that Quanta will repurchase under the ASR will be based on a volume-weighted average share price of its common stock during the term of the ASR, minus a discount and subject to other adjustments pursuant to the terms and conditions of the ASR. Final settlement of the ASR is scheduled to occur in the second quarter of 2016, but the ASR may be terminated early or extended in certain circumstances. At settlement, based on the final volume-weighted average share price, Quanta may be entitled to receive additional shares of its common stock from JPMorgan or, under certain circumstances, may be required to deliver shares or make a cash payment (at its option) to JPMorgan. In addition to the initial share delivery under the ASR, during the third and fourth quarters of 2015, Quanta repurchased 19.2 million shares of its common stock at a cost of $449.9 million in the open market under the 2015 Repurchase Program. During the fourth quarter of 2013, Quanta’s board of directors approved a stock repurchase program authorizing Quanta to purchase, from time to time through December 31, 2016, up to $500.0 million of its outstanding common stock (the 2013 Repurchase Program). During the year ended December 31, 2015, Quanta repurchased 14.4 million shares of its common stock at a cost of $406.5 million in the open market under the 2013 Repurchase Program. During the third quarter of 2015, Quanta completed the 2013 Repurchase Program. During the year ended December 31, 2015, Quanta repurchased a total of 59.3 million shares valued at $1.46 billion pursuant to both the 2013 Repurchase Program and the 2015 Repurchase Program. During the year ended December 31, 2014, Quanta repurchased approximately 3.0 million shares of its common stock under the 2013 Repurchase Program at a cost of $93.5 million. During the year ended December 31, 2013, Quanta did not repurchase any of its common stock. The shares and the related cost to acquire them have been accounted for as an adjustment to the balance of treasury stock. Non-controlling Interests Quanta holds investments in several joint ventures that provide infrastructure services under specific customer contracts. Quanta has determined that certain of these joint ventures are VIEs, with Quanta providing the majority of the infrastructure services to the joint venture, which management believes most significantly influences the economic performance of the joint venture. Management has concluded that Quanta is the primary beneficiary of each of the joint ventures determined to be VIEs and has accounted for each on a consolidated basis. The other parties’ equity interests in these joint ventures have been accounted for as non-controlling interests in the consolidated financial statements. Income attributable to the other joint venture members in the amounts of $10.9 million, $18.4 million and $19.4 million for the years ended December 31, 2015, 2014 and 2013, respectively, has been accounted for as a reduction of net income in deriving net income attributable to common stock. Equity in the consolidated assets and liabilities of these joint ventures that is attributable to the other joint venture members has been accounted for as non-controlling interests within total equity in the accompanying balance sheets. The carrying value of the investments held by Quanta in all of its VIEs was approximately $2.3 million and $11.1 million at December 31, 2015 and 2014. The carrying value of investments held by the non-controlling interests in these variable interest entities at December 31, 2015 and 2014 was $2.3 million and $11.1 million. During the years ended December 31, 2015, 2014 and 2013, distributions to non-controlling interests were $21.2 million, $14.4 million and $17.6 million. There were also contributions received from a joint venture partner of $2.3 million during the year ended December 31, 2015. There were no other changes in equity as a result of transfers to/from the non-controlling interests during the years ended December 31, 2015, 2014 and 2013. See Note 15 for further disclosures related to Quanta’s joint venture arrangements.

Equity-Based Compensation

Equity-Based Compensation	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity-Based Compensation	12. EQUITY-BASED COMPENSATION: Stock Incentive Plans On May 19, 2011, Quanta’s stockholders approved the 2011 Omnibus Equity Incentive Plan (the 2011 Plan). The 2011 Plan provides for the award of non-qualified stock options, incentive (qualified) stock options, stock appreciation rights, restricted stock, RSUs, stock bonus awards, performance compensation awards (including performance units and cash bonus awards) or any combination of the foregoing. The purpose of the 2011 Plan is to provide participants with additional performance incentives by increasing their proprietary interest in Quanta. Employees, directors, officers, consultants or advisors of Quanta or its affiliates are eligible to participate in the 2011 Plan, as are prospective employees, directors, officers, consultants or advisors of Quanta who have agreed to serve Quanta in those capacities. An aggregate of 11,750,000 shares of Quanta common stock may be issued pursuant to awards granted under the 2011 Plan. Additionally, pursuant to the Quanta Services, Inc. 2007 Stock Incentive Plan (the 2007 Plan), which was adopted on May 24, 2007, Quanta may award restricted stock, incentive stock options and non-qualified stock options to eligible employees, directors, and certain consultants and advisors. An aggregate of 4,000,000 shares of common stock may be issued pursuant to awards granted under the 2007 Plan. Quanta also has a Restricted Stock Unit Plan (the RSU Plan), pursuant to which RSUs may be awarded to certain employees and consultants of Quanta’s Canadian operations. The 2011 Plan, the 2007 Plan and the RSU Plan, together with certain plans assumed by Quanta in acquisitions, are referred to as the Plans. The Plans are administered by the Compensation Committee of the Board of Directors of Quanta. The Compensation Committee has, subject to applicable regulation and the terms of the Plans, the authority to grant awards under the Plans, to construe and interpret the Plans and to make all other determinations and take any and all actions necessary or advisable for the administration of the Plans. The Board also delegated to the Equity Grant Committee, a committee of the Board consisting of one or more directors, the authority to grant limited awards to eligible persons who are not executive officers or non-employee directors. Restricted Stock and RSUs to be Settled in Common Stock During the years ended December 31, 2015, 2014 and 2013, Quanta granted 1.3 million, 1.4 million and 1.4 million shares of restricted stock and RSUs to be settled in common stock under the Plans with weighted average grant date fair values of $27.64, $35.08 and $29.37 per share, respectively. The grant date fair value for awards of restricted stock and RSUs to be settled in common stock is based on the market value of Quanta common stock on the date of grant. Restricted stock and RSU awards to be settled in common stock are subject to forfeiture, restrictions on transfer and certain other conditions until vesting, which generally occurs in equal installments over a two-year or three-year period following the date of grant. During the restriction period, holders of restricted stock are entitled to vote and receive dividends, if applicable, on such shares. During the years ended December 31, 2015, 2014 and 2013, vesting activity consisted of 1.3 million, 1.1 million and 1.1 million shares of restricted stock and RSUs settled in common stock with an approximate fair value at the time of vesting of $35.9 million, $37.5 million and $30.8 million, respectively. Vesting activity during the year ended December 31, 2013 included compensation cost of approximately $4.3 million associated with the accelerated vesting of restricted stock and RSUs settled in common stock held by the former Executive Chairman of Quanta’s board of directors upon his retirement in May 2013. A summary of the activity for restricted stock and RSUs to be settled in common stock for the year ended December 31, 2015 is as follows (shares in thousands): Shares Weighted Average Grant Date Fair Value (Per share) Unvested at January 1, 2015 2,433 $ 31.29 Granted 1,307 $ 27.64 Vested (1,266 ) $ 28.37 Forfeited (97 ) $ 31.13 Unvested at December 31, 2015 2,377 $ 30.36 During the years ended December 31, 2015, 2014 and 2013, Quanta recognized $33.3 million, $35.0 million and $34.4 million of non-cash stock compensation expense related to restricted stock and RSUs to be settled in common stock. As of December 31, 2015, there was approximately $31.2 million of total unrecognized compensation cost related to unvested restricted stock and RSUs to be settled in common stock granted to both employees and non-employees. This cost is expected to be recognized over a weighted average period of 1.45 years. Performance Units to be Settled in Common Stock Performance units awarded pursuant to the 2011 Plan provide for the issuance of shares of common stock upon vesting. These performance units cliff-vest at the end of a three-year performance period based on achievement of three-year company financial performance targets and strategic initiatives established by the Compensation Committee. The final amount of earned and vested performance units can range from 0% to 200% of the initial amount awarded based on the level of performance, as determined by the Compensation Committee. During the years ended December 31, 2015 and 2014, Quanta granted 0.2 million and 0.1 million of performance units to be settled in common stock under the 2011 Plan with a weighted average grant date fair value of $28.16 and $35.20 per share. No performance units were granted during the year ended December 31, 2013. The grant date fair value for awards of performance units to be settled in common stock is based on the market value of Quanta common stock on the date of grant applied to the total number of shares that Quanta anticipates will fully vest. This fair value is expensed ratably over the vesting term and is adjusted for fair value changes so that the expense recognized for each award is equivalent to the fair value of the final number of earned and vested performance units. During the years ended December 31, 2015 and 2014, Quanta recognized $3.6 million and $2.4 million in compensation expense associated with performance units to be settled in common stock. No performance units vested, and no shares of common stock were issued in connection with performance units, during the years ended December 31, 2015 and 2014, as applicable performance periods had not yet concluded. RSUs to be Settled in Cash Certain RSUs granted by Quanta under the Plans are settled solely in cash. These cash-settled RSUs are intended to provide plan participants with cash performance incentives that are substantially equivalent to the risks and rewards of equity ownership in Quanta, typically vest in equal installments over a two-year or three-year period following the date of grant, and are subject to forfeiture under certain conditions, primarily termination of service. Additionally, subject to certain restrictions, Quanta’s non-employee directors may elect to cash settle a portion of their RSU awards, which generally vest upon conclusion of the director service year. For all RSUs settled in cash, the holders receive for each vested RSU an amount in cash equal to the fair market value on the settlement date of one share of Quanta common stock, as specified in the applicable award agreement. Compensation expense related to RSUs to be settled in cash was $4.0 million, $3.9 million and $3.1 million for the years ended December 31, 2015, 2014 and 2013. Such expense is recorded in selling, general and administrative expenses. RSUs that are anticipated to be settled in cash are not included in the calculation of earnings per share, and the estimated earned value of such RSUs is classified as a liability. Quanta paid $4.2 million, $3.1 million and $1.8 million to settle liabilities related to cash-settled RSUs in the years ended December 31, 2015, 2014 and 2013, respectively. Accrued liabilities for the estimated earned value of outstanding RSUs to be settled in cash were $2.7 million and $2.9 million at December 31, 2015 and 2014.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	13. EMPLOYEE BENEFIT PLANS: Unions’ Multiemployer Pension Plans Quanta contributes to a number of multiemployer defined benefit pension plans under the terms of collective bargaining agreements with various unions that represent certain of Quanta’s employees. Quanta’s multiemployer pension plan contribution rates generally are specified in the collective bargaining agreements (usually on an annual basis), and contributions are made to the plans on a “pay-as-you-go” basis based on its union employee payrolls. Quanta may also have additional liabilities imposed by law as a result of its participation in multiemployer defined benefit pension plans. The Employee Retirement Income Security Act of 1974, as amended by the Multiemployer Pension Plan Amendments Act of 1980, imposes certain liabilities upon an employer who is a contributor to a multiemployer pension plan if the employer withdraws from the plan or the plan is terminated or experiences a mass withdrawal. In the fourth quarter of 2011, Quanta recorded a partial withdrawal liability related to the withdrawal by certain Quanta subsidiaries from the Central States, Southeast and Southwest Areas Pension Plan (Central States Plan) following an amendment to the applicable collective bargaining agreement which eliminated their obligations to contribute to the Central States Plan. During the first quarter of 2014, Quanta recorded an adjustment to cost of services to increase the recognized withdrawal liability. Additional information regarding this withdrawal, as well as the withdrawal from the Central States Plan of a company acquired by Quanta in the fourth quarter of 2013, is provided in Collective Bargaining Agreements The Pension Protection Act of 2006 (PPA) also added special funding and operational rules generally applicable to plan years beginning after 2007 for multiemployer plans that are classified as “endangered,” “seriously endangered” or “critical” status based on multiple factors (including, for example, the plan’s funded percentage, cash flow position and whether it is projected to experience a minimum funding deficiency). Plans in these classifications must adopt measures to improve their funded status through a funding improvement or rehabilitation plan, as applicable, which may require additional contributions from employers (which may take the form of a surcharge on benefit contributions) and/or modifications to retiree benefits. Certain plans to which Quanta contributes or may contribute in the future are in “endangered,” “seriously endangered” or “critical” status. The amount of additional funds, if any, that Quanta may be obligated to contribute to these plans in the future cannot be estimated due to uncertainty of the future levels of work that require the specific use of union employees covered by these plans, as well as the future contribution levels and possible surcharges on contributions applicable to these plans. The following table summarizes plan information relating to Quanta’s participation in multiemployer defined benefit pension plans, including company contributions for the last three years, the status under the PPA of the plans and whether the plans are subject to a funding improvement or rehabilitation plan or contribution surcharges. The most recent PPA zone status available in 2015 and 2014 relates to the plan’s fiscal year-end in 2014 and 2013. Forms 5500 were not yet available for the plan years ending in 2015. The PPA zone status is based on information that Quanta received from the respective plans, as well as publicly available information on the U.S. Department of Labor website, and is certified by the plan’s actuary. Although multiple factors or tests may result in red zone or yellow zone status, plans in the red zone generally are less than 65 percent funded, plans in the yellow zone generally are less than 80 percent funded, and plans in the green zone generally are at least 80 percent funded. Under the PPA, red zone plans are classified as “critical” status, yellow zone plans are classified as “endangered” status and green zone plans are classified as neither “endangered” nor “critical” status. The “Subject to Financial Improvement/ Rehabilitation Plan” column indicates plans for which a financial improvement plan (FIP) or a rehabilitation plan (RP) is either pending or has been implemented. The last column lists the expiration dates of Quanta’s collective-bargaining agreements to which the plans are subject. Total contributions to these plans correspond to the number of union employees employed at any given time and the plans in which they participate and varies depending upon the location and number of ongoing projects at a given time and the need for union resources in connection with such projects. Information has been presented separately for individually significant plans and in the aggregate for all other plans. Fund Employee PPA Zone Subject Contributions (in thousands) Surcharge Expiration Date 2015 2014 2015 2014 2013 National Electrical Benefit Fund 53-0181657-001 Green Green No $ 21,200 $ 20,758 $ 17,268 No Varies through Laborers National Pension Fund 75-1280827-001 Green Green No 7,671 4,227 4,681 No Varies through Pipeline Industry Pension Fund 73-6146433-001 Green Green No 6,087 6,280 4,511 No Varies through Central Pension Fund of the IUOE & Participating Employers 36-6052390-001 Green Green No 5,677 7,847 4,259 No Varies through Midwest Operating Engineers Pension Trust Fund 36-6140097-001 Yellow Yellow Yes 3,294 497 217 Yes Varies through Laborers Pension Trust Fund for Northern California 94-6277608-001 Yellow Yellow Yes 2,603 1,357 987 Yes June 2019 Eighth District Electrical Pension Fund 84-6100393-001 Green Green No 2,544 2,192 1,790 No Varies through OE Pension Trust Fund 94-6090764-001 Red Red Yes 1,264 991 902 Yes June 2016 Operating Engineers Local 324 Pension Fund 38-1900637-001 Red Red Yes 1,231 1,086 818 Yes Varies through Local 697 IBEW and Electrical Industry Pension Fund 51-6133048-001 Yellow Yellow Yes 1,066 200 — Yes May 2018 Joint Pension Local Union 164 IBEW 22-6031199-001 Yellow Yellow Yes 513 1,816 222 No May 2017 Alaska Teamster—Employer Pension Plan 92-6003463-024 Red Red Yes 513 516 241 Yes June 2017 Michigan Upper Peninsula Intrl Brotherhood of Elec Workers Pension Plan 36-3020872-001 Yellow Yellow Yes 300 1,307 299 No May 2017 All other plans 23,052 22,130 18,859 Total $ 77,015 $ 71,204 $ 55,054 Quanta’s contributions to the following individually significant plans were five percent or more of the total contributions to these plans for the periods indicated based on the Forms 5500 for these plans for the years ended December 31, 2014 and 2013. Forms 5500 were not yet available for these plans for the year ended December 31, 2015. Pension Fund Plan Years in which Quanta Five Percent or More Pipeline Industry Pension Fund 2014 and 2013 Michigan Upper Peninsula Intrl Brotherhood of Elec Workers Pension Plan 2014 and 2013 Eighth District Electrical Pension Fund 2014 and 2013 Laborers National Pension Fund 2014 and 2013 Joint Pension Local Union 164 IBEW 2014 In addition to the contributions made to multiemployer defined benefit pension plans noted above, Quanta also contributed to multiemployer defined contribution or other benefit plans on behalf of certain union employees. Contributions to union multiemployer defined contribution or other benefit plans by Quanta were approximately $147.1 million, $129.0 million and $104.4 million for the years ended December 31, 2015, 2014 and 2013. Total contributions made to these plans for the years ended December 31, 2015, 2014 and 2013 correspond to the number of union employees employed at any given time and the plans in which they participate and varies depending upon the location and number of ongoing projects at a given time and the need for union resources in connection with such projects. Quanta 401(k) Plan Quanta maintains a 401(k) plan pursuant to which employees who are not provided retirement benefits through a collective bargaining agreement may make contributions through a payroll deduction. Quanta makes matching cash contributions of 100% of each employee’s contribution up to 3% of that employee’s salary and 50% of each employee’s contribution between 3% and 6% of such employee’s salary, up to the maximum amount permitted by law. Contributions to the 401(k) plan by Quanta were approximately $17.7 million, $13.9 million and $11.5 million for the years ended December 31, 2015, 2014 and 2013, respectively. Deferred Compensation Plan Quanta maintains a nonqualified deferred compensation plan pursuant to which non-employee directors and certain key employees, independent contractors and consultants may defer receipt of some or all of their cash compensation and/or settlement of their equity-based awards, subject to certain limitations. The plan provides for employer matching contributions for certain officers and employees whose benefits under the 401(k) plan are limited by federal tax law. Quanta may also make discretionary employer contributions to the plan. Matching contributions and discretionary employer contributions are subject to a vesting schedule, provided that vesting accelerates upon a change in control and the participant’s death or retirement. All matching and discretionary employer contributions, whether vested or not, are forfeited upon a participant’s termination of employment for cause or upon the participant engaging in competition with Quanta or any of its affiliates. Contributions to the deferred compensation plan by Quanta were approximately $1.0 million and $0.3 million during the years ended December 31, 2015 and 2014. There were no contributions to the plan during the year ended December 31, 2013. At December 31, 2015 and 2014, $11.7 million and $2.3 million were included in other long-term liabilities and $11.3 million and $2.0 million were included in other long-term assets related to obligations under this plan and related company-owned life insurance policies. Individuals participating in this plan receive distributions of their respective balances based on predetermined payout schedules or other events, as defined by the plan and are also able to direct investments made on their behalf among investment alternatives permitted from time to time under the plan.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	14. RELATED PARTY TRANSACTIONS: Certain of Quanta’s operating units have entered into related party lease arrangements for operational facilities, typically with prior owners of certain acquired businesses. These lease agreements generally have terms of up to five years and include renewal options. Related party lease expense for the years ended December 31, 2015, 2014 and 2013 was approximately $10.6 million, $8.5 million and $4.5 million, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	15. COMMITMENTS AND CONTINGENCIES: Investments in Affiliates and Other Entities As described in Note 11, Quanta holds investments in certain joint ventures with third parties for the purpose of providing infrastructure services under certain customer contracts. Losses incurred by these joint ventures are generally shared ratably based on the percentage ownership of the joint venture members. However, each member of the joint venture typically is jointly and severally liable for all of the obligations of the joint venture under the contract with the customer and therefore can be liable for full performance of the contract with the customer. In circumstances where Quanta’s participation in a joint venture qualifies as a general partnership, the joint venture partners are jointly and severally liable for all of the obligations of the joint venture including obligations owed to the customer or any other person or entity. Quanta is not aware of circumstances that would lead to future claims against it for material amounts in connection with these joint and several liabilities. In the joint venture arrangements entered into by Quanta, typically each joint venturer indemnifies the other party for any liabilities incurred in excess of the liabilities such other party is obligated to bear under the respective joint venture agreement. It is possible, however, that Quanta could be required to pay or perform obligations in excess of its share if the other joint venturer failed or refused to pay or perform its share of the obligations. Quanta is not aware of circumstances that would lead to future claims against it for material amounts that would not be indemnified. During the fourth quarter of 2014, a limited partnership in which Quanta is a partner was selected for an engineering, procurement and construction (EPC) electric transmission project to construct approximately 500 kilometers of transmission line and two 500 kV substations. Quanta will provide turnkey EPC services for the entire project. As of December 31, 2015, Quanta had outstanding capital commitments associated with investments in an unconsolidated affiliate related to this project as follows (in thousands): Capital Commitments Year Ending December 31: 2016 $ 8,909 2017 (1) 31,010 2018 — 2019 22,895 Total capital commitments associated with investments in an unconsolidated affiliate related to an EPC electrical transmission project $ 62,814 (1) This amount excludes a return of capital from an unconsolidated affiliate of approximately $40.9 million that is anticipated in August 2017. Additionally, as of December 31, 2015, Quanta had outstanding capital commitments associated with investments in unconsolidated affiliates related to planned midstream infrastructure projects of approximately $7.4 million, $1.3 million of which is expected to be paid in the first quarter of 2016. Quanta is unable to determine the exact timing of the remaining $6.1 million of these capital commitments but anticipates them to be paid by June 1, 2017. Leases Quanta leases certain land, buildings and equipment under non-cancelable lease agreements, including related party leases as discussed in Note 14. The terms of these agreements vary from lease to lease, including some with renewal options and escalation clauses. The following schedule shows the future minimum lease payments under these leases as of December 31, 2015 (in thousands): Operating Leases Year Ending December 31: 2016 $ 78,971 2017 56,488 2018 42,608 2019 25,065 2020 14,290 Thereafter 17,281 Total minimum lease payments $ 234,703 Rent expense related to operating leases was approximately $208.5 million, $161.5 million and $111.8 million for the years ended December 31, 2015, 2014 and 2013, respectively. Quanta has guaranteed the residual value on certain of its equipment operating leases. Quanta has agreed to pay any difference between this residual value and the fair market value of the underlying asset at the date of termination of the leases. At December 31, 2015, the maximum guaranteed residual value was approximately $487.1 million. Quanta believes that no significant payments will be made as a result of the difference between the fair market value of the leased equipment and the guaranteed residual value. However, there can be no assurance that significant payments will not be required in the future. Committed Capital Expenditures Quanta has capital commitments for the expansion of its vehicle fleet in order to accommodate manufacturer lead times on certain types of vehicles. As of December 31, 2015, Quanta issued approximately $2.3 million of production orders with expected delivery dates in 2016. Although Quanta has committed to purchase these vehicles at the time of their delivery, Quanta anticipates that these orders will be assigned to third party leasing companies and made available to Quanta under certain of its master equipment lease agreements, thereby releasing Quanta from its capital commitments. Legal Proceedings Quanta is from time to time party to various lawsuits, claims and other legal proceedings that arise in the ordinary course of business. These actions typically seek, among other things, compensation for alleged personal injury, breach of contract and/or property damages, employment-related damages, punitive damages, civil penalties or other losses, or injunctive or declaratory relief. With respect to all such lawsuits, claims and proceedings, Quanta records a reserve when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. In addition, Quanta discloses matters for which management believes a material loss is at least reasonably possible. Except as otherwise stated below, none of these proceedings, separately or in the aggregate, are expected to have a material adverse effect on Quanta’s consolidated financial position, results of operations or cash flows. In all instances, management has assessed the matter based on current information and made a judgment concerning its potential outcome, giving due consideration to the nature of the claim, the amount and nature of damages sought and the probability of success. Management’s judgment may prove materially inaccurate, and such judgment is made subject to the known uncertainties of litigation. Lorenzo Benton v. Telecom Network Specialists, Inc., et al. Additionally, in November 2007, TNS filed cross complaints for indemnity against the staffing agencies, which employed many of the individuals in question. In December 2012, the trial court heard cross-motions for summary judgment filed by TNS and the staffing agencies pertaining to TNS’s demand for indemnity. The court denied TNS’s motion and granted the motions filed by the staffing agencies. TNS appealed the court’s ruling, and in April 2015, the California Appellate Court reversed the trial court’s decision, vacated its award of attorneys’ fees, and instructed the trial court to reconsider its earlier ruling on TNS’s indemnity claims. At this time, Quanta does not believe this matter will have a material adverse effect on its consolidated financial position, results of operations or cash flows. SEC Notice Sunrise Powerlink Arbitration For additional information regarding other pending legal proceedings, see Collective Bargaining Agreements Concentrations of Credit Risk Quanta is subject to concentrations of credit risk related primarily to its cash and cash equivalents and accounts receivable, including amounts related to unbilled accounts receivable and costs and estimated earnings in excess of billings on uncompleted contracts. Substantially all of Quanta’s cash investments are managed by what it believes to be high credit quality financial institutions. In accordance with Quanta’s investment policies, these institutions are authorized to invest this cash in a diversified portfolio of what Quanta believes to be high quality investments, which consist primarily of interest-bearing demand deposits, money market mutual funds and investment grade commercial paper with original maturities of three months or less. Although Quanta does not currently believe the principal amount of these investments is subject to any material risk of loss, changes in economic conditions could impact the interest income Quanta receives from these investments. In addition, Quanta grants credit under normal payment terms, generally without collateral, to its customers, which include electric power and oil and gas companies, governmental entities, general contractors, and builders, owners and managers of commercial and industrial properties located primarily in the United States, Canada and Australia. Consequently, Quanta is subject to potential credit risk related to changes in business and economic factors throughout the United States, Canada and Australia, which may be heightened as a result of uncertain economic and financial market conditions that have existed in recent years. However, Quanta generally has certain statutory lien rights with respect to services provided. Historically, some of Quanta’s customers have experienced significant financial difficulties, and others may experience financial difficulties in the future. These difficulties expose Quanta to increased risk related to collectability of billed and unbilled receivables and costs and estimated earnings in excess of billings on uncompleted contracts for services Quanta has performed. At December 31, 2015, one customer accounted for approximately 12% of Quanta’s consolidated net position. The services provided to this customer related primarily to Quanta’s Electric Power Infrastructure Services segment. No customers represented 10% or more of Quanta’s revenues for the years ended December 31, 2015, 2014 and 2013, and no other customers represented 10% or more of Quanta’s consolidated net position as of December 31, 2015 or 2014. Self-Insurance As discussed in Note 2, Quanta is insured for employer’s liability, group health, general liability, auto liability and workers’ compensation claims. As of December 31, 2015 and 2014, the gross amount accrued for insurance claims totaled $209.0 million and $170.2 million, with $153.5 million and $130.8 million considered to be long-term and included in other non-current liabilities. Related insurance recoveries/receivables as of December 31, 2015 and 2014 were $8.6 million and $9.1 million, of which $0.6 million and $0.8 million were included in prepaid expenses and other current assets and $8.0 million and $8.3 million were included in other assets, net. Letters of Credit Certain of Quanta’s vendors require letters of credit to ensure reimbursement for amounts they are disbursing on its behalf, such as to beneficiaries under its self-funded insurance programs. In addition, from time to time, certain customers require Quanta to post letters of credit to ensure payment to its subcontractors and vendors and to guarantee performance under its contracts. Such letters of credit are generally issued by a bank or similar financial institution, typically pursuant to Quanta’s credit facility. Each letter of credit commits the issuer to pay specified amounts to the holder of the letter of credit if the holder demonstrates that Quanta has failed to perform specified actions. If this were to occur, Quanta would be required to reimburse the issuer of the letter of credit. Depending on the circumstances of such a reimbursement, Quanta may also be required to record a charge to earnings for the reimbursement. Quanta does not believe that it is likely that any material claims will be made under a letter of credit in the foreseeable future. As of December 31, 2015, Quanta had $307.0 million in outstanding letters of credit and bank guarantees under its credit facility to secure its casualty insurance program and various contractual commitments. These are irrevocable stand-by letters of credit with maturities generally expiring at various times throughout 2016. Upon maturity, it is expected that the majority of the letters of credit related to the casualty insurance program will be renewed for subsequent one-year periods. Performance Bonds and Parent Guarantees In certain circumstances, Quanta is required to provide performance bonds in connection with its contractual commitments. Quanta has indemnified its sureties for any expenses paid out under these performance bonds. These performance bonds expire at various times ranging from mechanical completion of the related projects to a period extending beyond contract completion in certain circumstances, and as such, a determination of maximum potential amounts outstanding requires the use of certain estimates and assumptions. Such amounts can also fluctuate from period to period based upon the mix and level of Quanta’s bonded operating activity. As of December 31, 2015, the total amount of the outstanding performance bonds was estimated to be approximately $2.6 billion. Quanta’s estimated maximum exposure as it relates to the value of the performance bonds outstanding is lowered on each bonded project as the cost to complete is reduced, and each of its commitments under the performance bonds generally extinguishes concurrently with the expiration of its related contractual obligation. The estimated cost to complete these bonded projects was approximately $906 million as of December 31, 2015. Quanta, from time to time, guarantees the obligations of its wholly owned subsidiaries, including obligations under certain contracts with customers, certain lease obligations and, in some states, obligations in connection with obtaining contractors’ licenses. Quanta is not aware of any material obligations for performance or payment asserted against it under any of these guarantees. Employment Agreements Quanta has various 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 of control of Quanta. Quanta may be obligated to pay certain amounts to such employees upon the occurrence of any of the defined events in the various employment agreements. Collective Bargaining Agreements Some of Quanta’s operating units are parties to various collective bargaining agreements with unions that represent certain of their employees. The collective bargaining agreements expire at various times and have typically been renegotiated and renewed on terms similar to those in the expiring agreements. From time to time, Quanta is a party to grievance actions based on claims arising out of the collective bargaining agreements. The agreements require the operating units to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to multiemployer pension plans and employee benefit trusts. Quanta’s multiemployer pension plan contribution rates generally are specified in the collective bargaining agreements (usually on an annual basis), and contributions are made to the plans on a “pay-as-you-go” basis based on its union employee payrolls. The location and number of union employees that Quanta employs at any given time and the plans in which they may participate vary depending on the projects Quanta has ongoing at any time and the need for union resources in connection with those projects. Therefore, Quanta is unable to accurately predict its union employee payroll and the amount of the resulting multiemployer pension plan contribution obligation for future periods. The PPA also added special funding and operational rules generally applicable to plan years beginning after 2007 for multiemployer plans that are classified as “endangered,” “seriously endangered” or “critical” status based on multiple factors (including, for example, the plan’s funded percentage, cash flow position and whether it is projected to experience a minimum funding deficiency). Plans in these classifications must adopt measures to improve their funded status through a funding improvement or rehabilitation plan, as applicable, which may require additional contributions from employers (which may take the form of a surcharge on benefit contributions) and/or modifications to retiree benefits. Certain plans to which Quanta contributes or may contribute in the future are in “endangered,” “seriously endangered” or “critical” status. The amount of additional funds, if any, that Quanta may be obligated to contribute to these plans in the future cannot be estimated due to uncertainty of the future levels of work that require the specific use of union employees covered by these plans, as well as the future contribution levels and possible surcharges on contributions applicable to these plans. Quanta may be subject to additional liabilities imposed by law as a result of its participation in multiemployer defined benefit pension plans. For example, the Employee Retirement Income Security Act of 1974, as amended by the Multiemployer Pension Plan Amendments Act of 1980, imposes certain liabilities upon an employer who is a contributor to a multiemployer pension plan if the employer withdraws from the plan or the plan is terminated or experiences a mass withdrawal. These liabilities include an allocable share of the unfunded vested benefits in the plan for all plan participants, not merely the benefits payable to a contributing employer’s own retirees. As a result, participating employers may bear a higher proportion of liability for unfunded vested benefits if other participating employers cease to contribute or withdraw, with the reallocation of liability being more acute in cases when a withdrawn employer is insolvent or otherwise fails to pay its withdrawal liability. Other than as described below, Quanta is not aware of any material amounts of withdrawal liability that have been incurred as a result of a withdrawal by any of Quanta’s operating units from any multiemployer defined benefit pension plans. 2011 Central States Plan Withdrawal Liability In connection with the partial withdrawal in 2011, Quanta recorded a withdrawal liability of approximately $32.6 million in the fourth quarter of 2011 based on estimates received from the Central States Plan. The Central States Plan subsequently asserted that the withdrawal of the PLCA members, and thus Quanta’s partial withdrawal, was not effective in 2011. The PLCA and Quanta believed at that time that a legally effective withdrawal had occurred during the fourth quarter of 2011, and this issue was litigated in the federal district court for the Northern District of Illinois, Eastern Division. In September 2013, the district court ruled in favor of the Central States Plan, and that decision was appealed by the PLCA. In July 2014, the Central States Plan provided Quanta with a Notice and Demand of partial withdrawal liability in the amount of $39.6 million. In September 2015, the United States Court of Appeals for the Seventh Circuit ruled in favor of the PLCA and reversed the district court’s ruling in favor of the Central States Plan. Based on the outcome of the appeal, in January 2016, the Central States Plan issued a revised assessment of Quanta’s withdrawal liability based on a 2011 partial withdrawal. The revised assessment claims $32.9 million of withdrawal liability against Quanta and recognizes payments of approximately $11.0 million made by Quanta against that amount as of the date of the revised assessment. Quanta is still in the process of evaluating the revised assessment and the effect on its ultimate liability stake. Separately, in December 2013, the Central States Plan filed lawsuits against two of Quanta’s other subsidiaries in connection with their withdrawal in 2012. In the first lawsuit, the Central States Plan alleged that the subsidiary elected to participate in the Central States Plan pursuant to the collective bargaining agreement under which it participated. Quanta argued that no such election was made and that any payments made to the Central States Plan were made in error. In July 2014, the parties reached an agreement to settle the lawsuit, and the court dismissed the case with prejudice. In the second lawsuit, the Central States Plan alleged that contributions made by the Quanta subsidiary to a new industry fund created after Quanta withdrew from the Central States Plan should have been made to the Central States Plan. This arguably would have extended the withdrawal date for this subsidiary to at least the end of 2013. Quanta disputed these allegations on the basis that it properly paid contributions to the new industry fund based on the terms of the collective bargaining agreement under which it participates and asserted that it terminated its obligation to contribute to the Central States Plan by the end of 2012. The parties both moved for summary judgment, and in March 2015, the court entered judgment in favor of Quanta. The Central States Plan filed a notice of appeal in April 2015, and in December 2015, the Central States Plan agreed to dismiss the appeal with prejudice. The ultimate liability associated with the complete withdrawal of Quanta’s subsidiaries from the Central States Plan will depend on various factors, including interpretations of the terms of the collective bargaining agreements under which the subsidiaries participated and whether exemptions from withdrawal liability applicable to construction industry employers will be available. In March 2014, the Central States Plan provided revised estimates indicating that the total withdrawal liability based on certain withdrawal scenarios from 2011 through 2014 could range between $40.1 million and $55.4 million, and, as discussed above, in January 2016, the Central States Plan provided a revised assessment of Quanta’s partial withdrawal liability. Although Quanta continues to dispute the total liability owed to the Central States Plan, it continues to make monthly payments while the parties determine the final withdrawal liability. The amount owed upon resolution of this matter will be reduced by the payments made. Based on the previous estimates of liability associated with a complete withdrawal from the Central States Plan, and allowing for the exclusion of amounts believed by management to have been improperly included in such estimate, Quanta recorded an adjustment to cost of services during the three months ended March 31, 2014 to increase the recognized withdrawal liability to an amount within the range communicated to Quanta by the Central States Plan. Quanta believes that the range of reasonable possible loss associated with a complete withdrawal from the Central States Plan is up to $55.4 million and is in the process of evaluating the effect of the revised assessment described above on this estimated range. Given the unknown nature of some of the factors mentioned above, the final withdrawal liability cannot yet be determined with certainty. Accordingly, it is reasonably possible that the amount owed upon final resolution of these matters could be materially higher than the expense Quanta has recognized through December 31, 2015. Central States Plan Grievance Matter 2013 Central States Plan Withdrawal Liability. Approximately $2.1 million of the purchase price for the acquired company was deposited into an escrow account on October 9, 2013 to fund any withdrawal obligation in excess of the $4.8 million initially demanded. Accordingly, the acquired company’s withdrawal from the Central States Plan is not expected to have a material impact on Quanta’s financial condition, results of operations or cash flows. Indemnities Quanta generally indemnifies its customers for the services it provides under its contracts, as well as other specified liabilities, which may subject Quanta to indemnity claims and liabilities and related litigation. Additionally, in connection with certain acquisitions and dispositions, Quanta has indemnified various parties against specified liabilities that those parties might incur in the future. The indemnities under acquisition or disposition agreements are usually contingent upon the other party incurring liabilities that reach specified thresholds. As of December 31, 2015, except as otherwise set forth above in Legal Proceedings In the normal course of Quanta’s acquisition transactions, Quanta obtains rights to indemnification from the sellers or former owners of acquired companies for certain risks, liabilities and obligations arising from their prior operations, such as performance, operational, safety, workforce or tax issues, some of which Quanta may not have discovered during due diligence. However, the indemnities may not cover all of Quanta’s exposure for such pre-acquisition matters and the indemnitors may be unwilling or unable to pay the amounts owed to Quanta. Accordingly, Quanta may incur expenses for which it is not reimbursed. Quanta is currently in the process of identifying certain pre-acquisition obligations associated with non-U.S. payroll taxes that may be due from a business acquired by Quanta in 2013. As of December 31, 2015, Quanta has recorded $11.4 million as its best estimate of the pre-acquisition tax obligations and a corresponding indemnification asset, as management expects to recover from the indemnity counterparties any amounts that Quanta may be required to pay in connection with any such obligations.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Information	16. SEGMENT INFORMATION: Quanta presents its operations under two reportable segments: (1) Electric Power Infrastructure Services and (2) Oil and Gas Infrastructure Services. This structure is generally based on the broad end-user markets for Quanta’s services. See Note 1 for additional information regarding Quanta’s reportable segments. Quanta’s segment results are derived from the types of services provided across its operating units in each of the end user markets described above. Quanta’s entrepreneurial business model allows each of its operating units to serve the same or similar customers and to provide a range of services across end user markets. Quanta’s operating units are organized into one of two internal divisions, namely, the Electric Power Infrastructure Services Division and the Oil and Gas Infrastructure Services Division. These internal divisions are closely aligned with the reportable segments described above based on their operating units’ predominant type of work. Reportable segment information, including revenues and operating income by type of work, is gathered from each operating unit for the purpose of evaluating segment performance in support of Quanta’s market strategies. These classifications of Quanta’s operating unit revenues by type of work for segment reporting purposes can at times require judgment on the part of management. Quanta’s operating units may perform joint infrastructure service projects for customers in multiple industries, deliver multiple types of network services under a single customer contract or provide service across industries, for example, joint trenching projects to install distribution lines for electric power and natural gas customers. In addition, Quanta’s integrated operations and common administrative support at each of its operating units require that certain allocations of shared and indirect costs, such as facility costs and indirect operating expenses, including depreciation and general and administrative costs, be made to determine operating segment profitability. Corporate costs, such as payroll and benefits, employee travel expenses, facility costs, professional fees, acquisition costs and amortization related to certain intangible assets are not allocated. Summarized financial information for Quanta’s reportable segments is presented in the following table (in thousands): Year Ended December 31, 2015 2014 2013 Revenues: Electric Power Infrastructure $ 4,937,289 $ 5,302,671 $ 4,541,962 Oil and Gas Infrastructure 2,635,147 2,444,558 1,869,615 Consolidated $ 7,572,436 $ 7,747,229 $ 6,411,577 Operating income (loss) Electric Power Infrastructure $ 362,328 $ 462,985 $ 523,355 Oil and Gas Infrastructure 142,929 162,797 138,543 Corporate and non-allocated costs (267,754 ) (196,722 ) (185,899 ) Consolidated $ 237,503 $ 429,060 $ 475,999 Depreciation: Electric Power Infrastructure $ 89,150 $ 76,214 $ 64,913 Oil and Gas Infrastructure 65,315 57,414 47,050 Corporate and non-allocated costs 8,380 7,478 6,867 Consolidated $ 162,845 $ 141,106 $ 118,830 Separate measures of Quanta’s assets and cash flows by reportable segment, including capital expenditures, are not produced or utilized by management to evaluate segment performance. Quanta’s fixed assets, which are held at the operating unit level, include operating machinery, equipment and vehicles, as well as office equipment, buildings and leasehold improvements, and are used on an interchangeable basis across its reportable segments. As such, for reporting purposes, total depreciation expense is allocated each quarter among Quanta’s reportable segments based on the ratio of each reportable segment’s revenue contribution to consolidated revenues. Foreign Operations During 2015, 2014, and 2013, Quanta derived $1.54 billion, $1.89 billion and $1.31 billion, respectively, of its revenues from foreign operations. Of Quanta’s foreign revenues, approximately 85%, 82% and 86% was earned in Canada during the years ended December 31, 2015, 2014 and 2013, respectively. In addition, Quanta held property and equipment of $317.6 million and $372.9 million in foreign countries, primarily Canada, as of December 31, 2015 and 2014.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	17. QUARTERLY FINANCIAL DATA (UNAUDITED): The table below sets forth the unaudited consolidated operating results by quarter for the years ended December 31, 2015 and 2014 (in thousands, except per share information). For the Three Months Ended March 31, June 30, September 30, December 31, 2015: Revenues $ 1,861,386 $ 1,872,340 $ 1,939,438 $ 1,899,272 Gross profit 237,906 227,505 235,215 223,039 Net income (loss) 58,185 49,565 218,956 (4,882 ) Net income (loss) attributable to common stock 53,484 46,109 216,388 (5,074 ) Net income (loss) from continuing operations attributable to common stock 47,689 32,007 43,176 (2,586 ) Earnings (loss) per share from continuing operations attributable to common stock — basic and diluted $ 0.22 $ 0.15 $ 0.23 $ (0.02 ) 2014: Revenues $ 1,735,448 $ 1,838,209 $ 2,145,958 $ 2,027,614 Gross profit 256,054 264,209 336,903 311,628 Net income 58,648 85,444 100,015 70,975 Net income attributable to common stock 54,408 81,082 94,648 66,576 Net income from continuing operations attributable to common stock 47,442 73,453 87,923 60,406 Earnings per share from continuing operations attributable to common stock — basic and diluted $ 0.22 $ 0.33 $ 0.40 $ 0.27 During the fourth quarter of 2015, Quanta recorded total asset impairment charges of $58.5 million ($44.6 million net of tax). These impairment charges related to goodwill, intangible assets and property and equipment. Included in these charges was a $39.8 million goodwill impairment and a $12.1 million impairment related to customer relationships, trade names and non-compete agreement intangible assets. These goodwill and intangible impairments primarily resulted from lower forecasted oil and gas services revenues for Quanta’s Gulf of Mexico operations and certain operations in Australia, due to the extended low commodity price environment. Additionally, Quanta recorded a property and equipment impairment of $6.6 million related to certain international renewable energy services operations. Additionally, during the third quarter of 2015, net income and net income attributable to common stock included an approximately $171 million gain on the sale, net of tax, of Quanta’s fiber optic licensing operations. During the third and fourth quarters of 2014, Quanta recorded charges of $52.5 million ($32.3 million net of tax) and $49.9 million ($30.3 million net of tax) associated with an electric power infrastructure services project completed in 2012. See Legal Proceedings — Sunrise Powerlink Arbitration The sum of the individual quarterly earnings per share amounts may not equal year-to-date earnings per share as each period’s computation is based on the weighted average number of shares outstanding during the period.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	18. SUBSEQUENT EVENTS: Acquisitions During the first quarter of 2016, Quanta has completed two acquisitions. Quanta acquired a full service medium and high voltage powerline contracting company located in the United States. The results of this company will generally be included in Quanta’s Electric Power Infrastructure Services segment. Quanta also acquired a pipeline service contractor located in the United States, the results of which will generally be included in Quanta’s Oil and Gas Infrastructure Services segment. The aggregate consideration paid for these acquisitions was approximately $41.5 million in cash, subject to certain adjustments and certain contingent consideration payments that may be payable by Quanta. As these transactions were effective during the first quarter of 2016, the results will be included in Quanta’s consolidated financial statements beginning on the respective dates of acquisition. These acquisitions should enable Quanta to further enhance its electric power and oil and gas infrastructure service offerings in the United States.

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements of Quanta include the accounts of Quanta Services, Inc. and its wholly owned subsidiaries, which are also referred to as its operating units. The consolidated financial statements also include the accounts of certain of Quanta’s investments in joint ventures, which are either consolidated or proportionately consolidated, as discussed in the following summary of significant accounting policies. Investments in affiliated entities in which Quanta does not have a controlling financial interest, but over which Quanta has significant influence, usually because Quanta holds a voting interest of between 20% and 50%, are accounted for using the equity method. All significant intercompany accounts and transactions have been eliminated in consolidation. Unless the context requires otherwise, references to Quanta include Quanta Services, Inc. and its consolidated subsidiaries.
Use of Estimates and Assumptions	Use of Estimates and Assumptions The preparation of financial statements in conformity with US GAAP requires the use of estimates and assumptions by management in determining the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities known to exist as of the date the financial statements are published, and the reported amounts of revenues and expenses recognized during the periods presented. Quanta reviews all significant estimates affecting its consolidated financial statements on a recurring basis and records the effect of any necessary adjustments prior to their publication. Judgments and estimates are based on Quanta’s beliefs and assumptions derived from information available at the time such judgments and estimates are made. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of financial statements. Estimates are primarily used in Quanta’s assessment of the allowance for doubtful accounts, valuation of inventory, useful lives of assets, fair value assumptions in analyzing goodwill, other intangibles and long-lived asset impairments, equity and other investments, loan receivables, purchase price allocations, liabilities for self-insured and other claims and guarantees, multiemployer pension plan withdrawal liabilities, revenue recognition for construction contracts inclusive of contractual change orders and claims, share-based compensation, operating results of reportable segments, as well as the provision for income taxes and the calculation of uncertain tax positions.
Cash and Cash Equivalents	Cash and Cash Equivalents Quanta had cash and cash equivalents of $128.8 million and $190.5 million as of December 31, 2015 and 2014. Cash consisting of interest-bearing demand deposits is carried at cost, which approximates fair value. Quanta considers all highly liquid investments with an original maturity of three months or less at the time of purchase to be cash equivalents, which are carried at fair value. At December 31, 2015 and 2014, cash equivalents were $1.4 million and $107.6 million and consisted primarily of money market mutual funds and are discussed further in Fair Value Measurements
Current and Long-Term Accounts and Notes Receivable and Allowance for Doubtful Accounts	Current and Long-Term Accounts and Notes Receivable and Allowance for Doubtful Accounts Quanta provides an allowance for doubtful accounts when collection of an account or note receivable is considered doubtful, and receivables are written off against the allowance when deemed uncollectible. Inherent in the assessment of the allowance for doubtful accounts are certain judgments and estimates regarding, among other factors, the customer’s access to capital, the customer’s willingness or ability to pay, general economic and market conditions, the ongoing relationship with the customer and uncertainties related to the resolution of disputed matters. Quanta considers accounts receivable delinquent after 30 days but does not generally include delinquent accounts in its analysis of the allowance for doubtful accounts unless the accounts receivable have been outstanding for at least 90 days. In addition to balances that have been outstanding for 90 days or more, Quanta also includes accounts receivable balances that relate to customers in bankruptcy or with other known difficulties in its analysis of the allowance for doubtful accounts. Material changes in Quanta’s customers’ business or cash flows, which may be impacted by negative economic and market conditions, could affect Quanta’s ability to collect amounts due from them. As of December 31, 2015 and 2014, Quanta had allowances for doubtful accounts on current receivables of approximately $5.2 million and $6.2 million. Long-term accounts receivable are included within other assets, net on the consolidated balance sheets. Should customers experience financial difficulties or file for bankruptcy, or should anticipated recoveries relating to receivables in existing bankruptcies or other workout situations fail to materialize, Quanta could experience reduced cash flows and losses in excess of current allowances provided. The balances billed but not paid by customers pursuant to retainage provisions in certain contracts are generally due upon completion of the contracts and acceptance by the customer. Based on Quanta’s experience with similar contracts in recent years, the majority of the retainage balances at each balance sheet date are expected to be collected within the next twelve months. Current retainage balances as of December 31, 2015 and 2014 were approximately $250.1 million and $307.3 million and were included in accounts receivable. Retainage balances with settlement dates beyond the next twelve months were included in other assets, net, and as of December 31, 2015 and 2014 were $4.5 million and $19.6 million. Within accounts receivable, Quanta recognizes unbilled receivables in circumstances such as when revenues have been earned and recorded but the amount cannot be billed under the terms of the contract until a later date; costs have been incurred but are yet to be billed under cost-reimbursement type contracts; or amounts arise from routine lags in billing (for example, work completed one month but not billed until the next month). These balances do not include revenues accrued for work performed under fixed-price contracts as these amounts are recorded as costs and estimated earnings in excess of billings on uncompleted contracts. At December 31, 2015 and 2014, the balances of unbilled receivables included in accounts receivable were approximately $233.6 million and $163.1 million.
Inventories	Inventories Inventories consist primarily of parts and supplies held for use in the ordinary course of business, which are valued by Quanta at the lower of cost or market as determined by using either the first-in, first-out (FIFO) method or the average costing method. Inventories also include certain job specific materials not yet installed which are valued using the specific identification method.
Property and Equipment	Property and Equipment Property and equipment are stated at cost, and depreciation is computed using the straight-line method, net of estimated salvage values, over the estimated useful lives of the assets. Leasehold improvements are capitalized and amortized over the lesser of the life of the lease or the estimated useful life of the asset. Depreciation expense related to property and equipment was approximately $162.8 million, $141.1 million and $118.8 million for the years ended December 31, 2015, 2014 and 2013, respectively. Accrued capital expenditures were $5.8 million and $11.8 million as of December 31, 2015 and 2014. The impact of these items has been excluded from Quanta’s capital expenditures on its consolidated statements of cash flows due to their non-cash nature. Expenditures for repairs and maintenance are charged to expense when incurred. Expenditures for major renewals and betterments, which extend the useful lives of existing equipment, are capitalized and depreciated over the adjusted remaining useful lives of the assets. Upon retirement or disposition of property and equipment, the cost and related accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in selling, general and administrative expenses. Management reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount may not be realizable. Quanta recognized an impairment charge of $6.6 million during the quarter ended December 31, 2015 related to certain of Quanta’s international renewable energy services operations based on the estimated future undiscounted cash flows associated with the asset group as compared to the carrying value before the impairment. Quanta did not recognize any asset impairments during the years ended December 31, 2014 or 2013. When an evaluation is required, the estimated future undiscounted cash flows associated with the asset group are compared to the asset group’s carrying amount to determine if an impairment of such asset group is necessary. The effect of any impairment involves expensing the difference between the fair value of such asset group and its carrying value in the period incurred.
Other Assets, Net	Other Assets, Net Other assets, net consists primarily of long-term receivables, debt issuance costs, equity and other investments, refundable security deposits for leased properties and insurance claims in excess of deductibles that are due from Quanta’s insurers.
Debt Issuance Costs	Debt Issuance Costs Capitalized debt issuance costs related to Quanta’s credit facility and any other debt outstanding at a given balance sheet date are included in other assets, net and are amortized into interest expense on a straight-line basis over the terms of the respective agreements giving rise to the debt issuance costs, which Quanta believes approximates the effective interest rate method. During 2015, Quanta incurred $3.8 million of debt issuance costs related to the amendment and restatement of its credit agreement and recorded a nominal charge to interest expense for the write-off of a portion of the debt issuance costs related to the prior facility. During 2013, Quanta incurred $3.2 million of debt issuance costs related to the amendment and restatement of its credit agreement and recorded a nominal charge to interest expense for the write-off of a portion of the debt issuance costs related to the prior facility. As of December 31, 2015 and 2014, capitalized debt issuance costs were $11.4 million and $7.6 million, with accumulated amortization of $4.8 million and $3.5 million. For the years ended December 31, 2015, 2014 and 2013, amortization expense related to capitalized debt issuance costs was $1.3 million, $1.1 million and $1.1 million, respectively.
Goodwill and Other Intangibles	Goodwill and Other Intangibles Quanta has recorded goodwill in connection with its historical acquisitions of companies. Upon acquisition, these companies were either combined into one of Quanta’s existing operating units or managed on a stand-alone basis as an individual operating unit. Goodwill recorded in connection with these acquisitions is subject to an annual assessment for impairment, which Quanta performs at the operating unit level for each operating unit that carries a balance of goodwill. Each of Quanta’s operating units is organized into one of two internal divisions: the Electric Power Infrastructure Services Division and the Oil and Gas Infrastructure Services Division. As most of the companies acquired by Quanta provide multiple types of services for multiple types of customers, these divisional designations are based on the predominant type of work performed by each operating unit at the point in time the divisional designation is made. Goodwill is required to be measured for impairment at the reporting unit level, which represents the operating segment level or one level below the operating segment level for which discrete financial information is available. Quanta has determined that its individual operating units represent its reporting units for the purpose of assessing goodwill impairments. Quanta has the option to first assess qualitative factors to determine whether it is necessary to perform the two-step fair value-based impairment test described below. If Quanta believes that, as a result of its qualitative assessment, it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the quantitative impairment test is required. Otherwise, no further testing is required. Quanta can choose to perform the qualitative assessment on none, some or all of its reporting units. Quanta can also bypass the qualitative assessment for any reporting unit in any period and proceed directly to step one of the impairment test, and then resume the qualitative assessment in any subsequent period. Qualitative indicators including deterioration in macroeconomic conditions, declining financial performance, or a sustained decrease in share price, among other things, may trigger the need for annual or interim impairment testing of goodwill associated with one or all of the reporting units. Quanta’s goodwill impairment assessment is performed at year-end, or more frequently if events or circumstances arise which indicate that goodwill may be impaired. For instance, a decrease in Quanta’s market capitalization below book value, a significant change in business climate or loss of a significant customer, as well as the qualitative indicators referenced above, may trigger the need for interim impairment testing of goodwill for one or all of its reporting units. The first step of the two-step fair value-based test involves comparing the fair value of each of Quanta’s reporting units with its carrying value, including goodwill. If the carrying value of the reporting unit exceeds its fair value, the second step is performed. The second step compares the carrying amount of the reporting unit’s goodwill to the implied fair value of its goodwill. If the implied fair value of goodwill is less than the carrying amount, an impairment loss would be recorded as a reduction to goodwill with a corresponding charge to operating expense. Quanta determines the fair value of its reporting units using a weighted combination of the discounted cash flow, market multiple and market capitalization valuation approaches, with heavier weighting on the discounted cash flow method, as in management’s opinion, this method currently results in the most accurate calculation of a reporting unit’s fair value. Determining the fair value of a reporting unit requires judgment and the use of significant estimates and assumptions. Such estimates and assumptions include revenue growth rates, operating margins, discount rates, weighted average costs of capital and future market conditions, among others. Quanta believes the estimates and assumptions used in its impairment assessments are reasonable and based on available market information, but variations in any of the assumptions could result in materially different calculations of fair value and determinations of whether or not an impairment is indicated. Under the discounted cash flow method, Quanta determines fair value based on the estimated future cash flows of each reporting unit, discounted to present value using risk-adjusted industry discount rates, which reflect the overall level of inherent risk of a reporting unit and the rate of return an outside investor would expect to earn. Cash flow projections are derived from budgeted amounts and operating forecasts (typically a one-year model) plus an estimate of later period cash flows, all of which are evaluated by management. Subsequent period cash flows are developed for each reporting unit using growth rates that management believes are reasonably likely to occur, along with a terminal value derived from the reporting unit’s earnings before interest, taxes, depreciation and amortization (EBITDA). The EBITDA multiples for each reporting unit are based on trailing twelve-month comparable industry data. Under the market multiple and market capitalization approaches, Quanta determines the estimated fair value of each of its reporting units by applying transaction multiples to each reporting unit’s projected EBITDA and then averaging that estimate with similar historical calculations using either a one, two or three year average. For the market capitalization approach, Quanta adds a reasonable control premium, which is estimated as the premium that would be received in a sale of the reporting unit in an orderly transaction between market participants. The projected cash flows and estimated levels of EBITDA by reporting unit were used to determine fair value under the three approaches discussed herein. The following table presents the significant estimates used by management in determining the fair values of Quanta’s reporting units at December 31, 2015, 2014 and 2013: 2015 2014 2013 Years of cash flows before terminal value 5 5 5 Discount rates 12% to 16% 12% to 14% 12% to 14% EBITDA multiples 5.0 to 6.5 5.0 to 6.0 5.0 to 8.0 Weighting of three approaches: Discounted cash flows 70% 70% 70% Market multiple 15% 15% 15% Market capitalization 15% 15% 15% For recently acquired reporting units, a step one impairment test may indicate an implied fair value that is substantially similar to the reporting unit’s carrying value. Such similarities in value are generally an indication that management’s estimates of future cash flows associated with the recently acquired reporting unit remain relatively consistent with the assumptions that were used to derive its initial fair value. During the fourth quarter of 2015, a two-step fair-value based goodwill impairment analysis was performed for each of Quanta’s reporting units, and no reporting units were evaluated solely on a qualitative basis. Step one of the analysis indicated that the implied fair value of each of Quanta’s reporting units, other than recently acquired reporting units and two other reporting units described below, was substantially in excess of its carrying value. After performing step two of the analysis, management concluded that goodwill was impaired at two reporting units in Quanta’s Oil and Gas Infrastructure Services Division. Accordingly, during the fourth quarter of 2015, Quanta recorded a $39.8 million non-cash charge for the impairment of goodwill which primarily resulted from lower forecasted oil and gas services revenues for its Gulf of Mexico operations and certain operations in Australia, due to the extended low commodity price environment. As discussed generally above, when evaluating the 2015 step one impairment test results, management considered many factors in determining whether or not an impairment of goodwill for any reporting unit was reasonably likely to occur in future periods, including future market conditions and the economic environment in which Quanta’s reporting units were operating. Additionally, management considered the sensitivity of its fair value estimates to changes in certain valuation assumptions. After giving consideration to a 10% decrease in the fair value of each of Quanta’s reporting units, the results of the assessment at December 31, 2015 did not change. However, circumstances such as market declines, unfavorable economic conditions, the loss of a major customer or other factors could increase the risk of impairment of goodwill in future periods. If an operating unit experiences prolonged periods of declining revenues, operating margins or both, it may be at risk of failing step one of the goodwill impairment test. Certain operating units have experienced declines over the short-term due to challenging macroeconomic conditions in certain geographic areas, the decline in oil prices which has impacted customer spending, and delays due to regulatory and permitting issues. Quanta will continue to monitor these conditions and others to determine if it is necessary to perform step two of the fair-value based impairment test for one or more operating units. The goodwill analysis performed for each reporting unit was based on estimates and comparisons obtained from the electric power and oil and gas industries. Quanta assigned a higher weighting to the discounted cash flow approach in all periods to reflect increased expectations of market value being determined from a “held and used” model. As stated previously, cash flows are derived from budgeted amounts and operating forecasts that have been evaluated by management. In connection with the 2015 assessment, projected annual growth rates by reporting unit varied widely with ranges from (28%) to 54%. Quanta’s intangible assets include customer relationships, backlog, trade names, non-compete agreements, patented rights and developed technology, all subject to amortization. The value of customer relationships is estimated as of the date a business is acquired based on the value-in-use concept utilizing the income approach, specifically the excess earnings method. The excess earnings analysis consists of discounting to present value the projected cash flows attributable to the customer relationships, with consideration given to customer contract renewals and estimated customer attrition rates, the importance or lack thereof of existing customer relationships to Quanta’s business plan, income taxes and required rates of return. Quanta values backlog for acquired businesses as of the acquisition date based upon the contractual nature of the backlog within each service line, using the income approach to discount back to present value the cash flows attributable to the backlog. The value of trade names is estimated using the relief-from-royalty method of the income approach. This approach is based on the assumption that in lieu of ownership, a company would be willing to pay a royalty in order to exploit the related benefits of this intangible asset. Quanta amortizes intangible assets based upon the estimated consumption of the economic benefits of each intangible asset, or on a straight-line basis if the pattern of economic benefits consumption cannot otherwise be reliably estimated. Intangible assets subject to amortization are reviewed for impairment and are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. For instance, a significant change in business climate or a loss of a significant customer, among other things, may trigger the need for interim impairment testing of intangible assets. An impairment loss would be recognized if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its fair value. During the fourth quarter of 2015, Quanta recorded an impairment charge of $12.1 million related to customer relationships, trade names and non-compete agreement intangible assets. These intangible asset impairments primarily resulted from lower forecasted oil and gas services revenues for Quanta’s Gulf of Mexico operations and certain operations in Australia, due to the extended low commodity price environment. The two reporting units impacted are in Quanta’s Oil and Gas Infrastructure Services Division.
Investments in Affiliates and Other Entities	Investments in Affiliates and Other Entities In the normal course of business, Quanta enters into various types of investment arrangements, each having unique terms and conditions. These investments may include equity interests held by Quanta in business entities, including general or limited partnerships, contractual joint ventures, or other forms of equity or profit participation. These investments may also include Quanta’s participation in different financing structures such as the extension of loans to project specific entities, the acquisition of convertible notes issued by project specific entities, or other strategic financing arrangements. Quanta determines whether such investments involve a variable interest entity (VIE) based on the characteristics of the subject entity. If the entity is determined to be a VIE, then management determines if Quanta is the primary beneficiary of the entity and whether or not consolidation of the VIE is required. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the activities of a VIE that most significantly affect the VIE’s economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, in either case that could potentially be significant to the VIE. When Quanta is deemed to be the primary beneficiary, the VIE is consolidated and the other party’s equity interest in the VIE is accounted for as a non-controlling interest. In cases where Quanta determines that it has an undivided interest in the assets, liabilities, revenues and profits of an unincorporated VIE (e.g., a general partnership interest), such amounts are consolidated on a basis proportional to Quanta’s ownership interest in the unincorporated entity. Investments in entities of which Quanta is not the primary beneficiary, but over which Quanta has the ability to exercise significant influence, are accounted for using the equity method of accounting. Quanta’s share of net income or losses from unconsolidated equity investments is included in equity in earnings (losses) of unconsolidated affiliates in the consolidated statements of operations when applicable. Equity investments are reviewed for impairment by assessing whether any decline in the fair value of the investment below the carrying value is other than temporary. In making this determination, factors such as the ability to recover the carrying amount of the investment and the inability of the investee to sustain an earnings capacity are evaluated in determining whether a loss in value should be recognized. Any impairment losses related to investments would be recognized in other expense. Equity method investments are carried at original cost and are included in other assets, net in the consolidated balance sheet and are adjusted for Quanta’s proportionate share of the investees’ income, losses and distributions. On December 6, 2013, Quanta sold all of its equity ownership interest in Howard Midstream Energy Partners, LLC (HEP) for proceeds of approximately $220.9 million, which resulted in a pre-tax gain of approximately $112.7 million. HEP is engaged in the business of owning, operating and constructing midstream plant and pipeline assets in the oil and gas industry. Quanta held an equity ownership interest of approximately 31% in HEP.
Revenue Recognition	Revenue Recognition Through its Electric Power Infrastructure Services and Oil and Gas Infrastructure Services segments, Quanta designs, installs and maintains networks for customers in the electric power and oil and gas industries. These services may be provided pursuant to master service agreements, repair and maintenance contracts and fixed price and non-fixed price installation contracts. Pricing under these contracts may be competitive unit price, cost-plus/hourly (or time and materials basis) or fixed price (or lump sum basis), and the final terms and prices of these contracts are frequently negotiated with the customer. Under unit-based contracts, the utilization of an output-based measurement is appropriate for revenue recognition. Under these contracts, Quanta recognizes revenue as units are completed based on pricing established between Quanta and the customer for each unit of delivery, which best reflects the pattern in which the obligation to the customer is fulfilled. Under cost-plus/hourly and time and materials type contracts, Quanta recognizes revenue on an input basis, as labor hours are incurred and services are performed. Revenues from fixed price contracts are recognized using the percentage-of-completion method, measured by the percentage of costs incurred to date to total estimated costs for each contract. These contracts provide for a fixed amount of revenues for the entire project. Such contracts provide that the customer accept completion of progress to date and compensate Quanta for services rendered, which may be measured in terms of units installed, hours expended or some other measure of progress. Contract costs include all direct materials, labor and subcontract costs and those indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and depreciation costs. Much of the material associated with Quanta’s work is owner-furnished and is therefore not included in contract revenues and costs. The cost estimation process is based on professional knowledge and experience of Quanta’s engineers, project managers and financial professionals. Changes in job performance, job conditions and final contract settlements are factors that influence management’s assessment of total contract value and the total estimated costs to complete those contracts and therefore, Quanta’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. These factors are routinely evaluated on a project by project basis throughout the project term, and the impact of corresponding revisions in management’s estimates of contract value, contract cost and contract profit are recorded as necessary in the period in which the revisions are determined. 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. Quanta’s operating results for the years ended December 31, 2015 and 2014 were impacted by less than 5% as a result of changes in contract estimates related to projects that were in progress at December 31, 2014 and 2013. The current asset “Costs and estimated earnings in excess of billings on uncompleted contracts” represents revenues recognized in excess of amounts billed for fixed price contracts. The current liability “Billings in excess of costs and estimated earnings on uncompleted contracts” represents billings in excess of revenues recognized for fixed price contracts. Quanta may incur costs subject to change orders, whether approved or unapproved by the customer, and/or claims related to certain contracts. Quanta determines the probability that such costs will be recovered based upon evidence such as past practices with the customer, specific discussions or preliminary negotiations with the customer or verbal approvals. Quanta treats items as a cost of contract performance in the period incurred if it is not probable that the costs will be recovered or will recognize revenue if it is probable that the contract price will be adjusted and can be reliably estimated. As of December 31, 2015 and 2014, Quanta had approximately $137.2 million and $106.8 million of change orders and/or claims that had been included as contract price adjustments on certain contracts which were in the process of being negotiated in the normal course of business. These aggregate contract price adjustments represent management’s best estimate of additional contract revenues which have been earned and which management believes are probable of collection. The amounts ultimately realized by Quanta upon final acceptance by its customers could be higher or lower than such estimated amounts.
Income Taxes	Income Taxes Quanta follows the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recorded for future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the underlying assets or liabilities are recovered or settled. Quanta regularly evaluates valuation allowances established for deferred tax assets for which future realization is uncertain. The estimation of required valuation allowances includes estimates of future taxable income. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Quanta considers projected future taxable income and tax planning strategies in making this assessment. If actual future taxable income differs from these estimates, Quanta may not realize deferred tax assets to the extent estimated. Quanta records reserves for income taxes related to certain tax positions in those instances where Quanta considers it more likely than not that additional taxes may be due in excess of amounts reflected on income tax returns filed. When recording reserves for expected tax consequences of uncertain positions, Quanta assumes that taxing authorities have full knowledge of the position and all relevant facts. Quanta continually reviews exposure to additional tax obligations, and as further information is known or events occur, changes in tax reserves may be recorded. To the extent interest and penalties may be assessed by taxing authorities on any underpayment of income tax, such amounts have been accrued and are classified in the provision for income taxes. As of December 31, 2015, the total amount of unrecognized tax benefits relating to uncertain tax positions was $54.5 million, an increase from December 31, 2014 of $3.9 million. This increase in unrecognized tax benefits resulted primarily from a $5.3 million increase due to tax positions expected to be taken for 2015, partially offset by a $1.3 million decrease due to audit settlements. Quanta is currently under examination by the Internal Revenue Service (IRS) for tax years 2010, 2011 and 2012, and the federal statute of limitations for examination of all subsequent tax years remains open. Additionally, certain subsidiaries are under examination by various U.S. state, Canadian and other foreign tax authorities for multiple periods. Quanta believes it is reasonably possible that within the next 12 months unrecognized tax benefits may decrease by up to $27.5 million as a result of settlement of these examinations or as a result of the expiration of certain statute of limitations periods. The income tax laws and regulations are voluminous and are often ambiguous. As such, Quanta is required to make many subjective assumptions and judgments regarding its tax positions that could materially affect amounts recognized in its future consolidated balance sheets and statements of operations and comprehensive income.
Earnings Per Share	Earnings Per Share Basic earnings per share is computed using the weighted average number of common shares outstanding during the period, and diluted earnings per share is computed using the weighted average number of common shares outstanding during the period adjusted for all potentially dilutive common stock equivalents, except in cases where the effect of the common stock equivalents would be antidilutive.
Self-Insurance	Self-Insurance Quanta is insured for employer’s liability, general liability, auto liability and workers’ compensation claims. Under these programs, the deductibles for general liability and auto liability are $10.0 million per occurrence, the deductible for workers’ compensation is $5.0 million per occurrence, and the deductible for employer’s liability is $1.0 million per occurrence. For the 2012-2013 policy year, deductibles for general liability, auto liability and workers’ compensation were $5.0 million per occurrence, and the deductible for employer’s liability was $1.0 million per occurrence. Quanta is generally self-insured for all claims that do not exceed the amount of the applicable deductible. Quanta also has employee health care benefit plans for most employees not subject to collective bargaining agreements, of which the primary plan is subject to a deductible of $375,000 per claimant per year. Losses under all of these insurance programs are accrued based upon Quanta’s estimate of the ultimate liability for claims reported and an estimate of claims incurred but not reported, with assistance from third-party actuaries. These insurance liabilities are difficult to assess and estimate due to unknown factors, including the severity of an injury, the extent of damage, the determination of Quanta’s liability in proportion to other parties and the number of incidents not reported. The accruals are based upon known facts and historical trends, and management believes such accruals are adequate.
Collective Bargaining Agreements	Collective Bargaining Agreements Some of Quanta’s operating units are parties to various collective bargaining agreements with unions that represent certain of their employees. The collective bargaining agreements expire at various times and have typically been renegotiated and renewed on terms similar to those in the expiring agreements. The agreements require the operating units to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to multiemployer pension plans and employee benefit trusts. Quanta’s multiemployer pension plan contribution rates generally are specified in the collective bargaining agreements (usually on an annual basis), and contributions are made to the plans on a “pay-as-you-go” basis based on its union employee payrolls. The location and number of union employees that Quanta employs at any given time and the plans in which they may participate vary depending on the projects Quanta has ongoing at that time and the need for union resources in connection with those projects. Therefore, Quanta is unable to accurately predict the union employee payroll and the amount of the resulting multiemployer pension plan contribution obligation for future periods.
Stock-Based Compensation	Stock-Based Compensation Quanta recognizes compensation expense for restricted stock, restricted stock units (RSUs) and performance units to be settled in common stock based on the fair value of the awards granted at the date of grant, net of estimated forfeitures. The fair value of restricted stock awards, RSUs and performance units to be settled in common stock is determined based on the number of shares, RSUs or performance units granted and the closing price of Quanta’s common stock on the date of grant. An estimate of future forfeitures is required in determining the period expense. Quanta uses historical data to estimate the forfeiture rate; however, these estimates are subject to change and may impact the value that will ultimately be realized as compensation expense. The resulting compensation expense from discretionary awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period, while compensation expense from performance-based restricted stock awards is recognized using the graded vesting method over the requisite service period. The cash flows resulting from the tax deductions in excess of the compensation expense recognized for restricted stock, RSUs and performance units to be settled in common stock and stock options (excess tax benefit) are classified as financing cash flows. Compensation expense associated with liability based awards, such as RSUs that are expected to or may settle in cash, is recognized based on a remeasurement of the fair value of the award at the end of each reporting period. Upon settlement, the holders receive for each RSU an amount in cash equal to the fair market value on the settlement date of one share of Quanta common stock, as specified in the applicable award agreement. For additional information on Quanta’s restricted stock, RSUs, and performance unit awards, see Note 12.
Functional Currency and Translation of Financial Statements	Functional Currency and Translation of Financial Statements The U.S. dollar is the functional currency for the majority of Quanta’s operations, which are primarily located within the United States. The functional currency for Quanta’s foreign operations, which are primarily located in Canada and Australia, is typically the currency of the country in which the foreign operating unit is located. Generally, the currency in which the operating unit transacts the majority of its activities, including billings, financing, payroll and other expenditures, would be considered the functional currency. The treatment of foreign currency translation gains or losses is dependent upon management’s determination of the functional currency of each operating unit. In preparing the consolidated financial statements, Quanta translates the financial statements of its foreign operating units from their functional currency into U.S. dollars. Statements of operations, comprehensive income and cash flows are translated at average monthly rates, while balance sheets are translated at month-end exchange rates. The translation of the balance sheets results in translation gains or losses, which are included as a separate component of equity under the caption “Accumulated other comprehensive income (loss).” Gains and losses arising from transactions which are not denominated in the operating units’ functional currencies are included within other income (expense) in the statements of operations.
Derivatives	Derivatives From time to time, Quanta enters into forward currency contracts that qualify as derivatives in order to hedge the risks associated with fluctuations in foreign currency exchange rates related to certain forecasted foreign currency denominated transactions. Quanta does not enter into derivative transactions for speculative purposes; however, for accounting purposes, certain transactions may not meet the criteria for cash flow hedge accounting. For a hedge to qualify for cash flow hedge accounting treatment, a hedge must be documented at the inception of the contract, with the objective and strategy stated, along with an explicit description of the methodology used to assess hedge effectiveness. The dates (or periods) for the expected forecasted events and the nature of the exposure involved (including quantitative measures of the size of the exposure) must also be documented. At the inception of the hedge and on an ongoing basis, the hedge must be deemed to be “highly effective” at minimizing the risk of the identified exposure. Effectiveness measures relate the gains or losses of the derivative to changes in the cash flows associated with the hedged item, and the forecasted transaction must be probable of occurring. For forward contracts that qualify as cash flow hedges, Quanta accounts for the change in fair value of the forward contracts directly in equity as part of accumulated other comprehensive income (loss). Any ineffective portion of cash flow hedges is recognized in earnings in the period in which ineffectiveness occurs. For instance, if a forward contract is discontinued as a cash flow hedge because it is probable that the original forecasted transaction will not occur by the end of the originally specified time period, the related amounts in accumulated other comprehensive income (loss) would be reclassified to other income (expense) in the consolidated statement of operations in the period such determination is made. When a forecasted transaction occurs, the portion of the accumulated gain or loss applicable to the forecasted transaction is reclassified from equity to earnings. Changes in fair value related to transactions that do not meet the criteria for cash flow hedge accounting are recorded in the consolidated statements of operations and are included in other income (expense).
Comprehensive Income	Comprehensive Income Components of comprehensive income include all changes in equity during a period except those resulting from changes in Quanta’s capital related accounts. Quanta records other comprehensive income (loss) for foreign currency translation adjustments related to its foreign operations and for other revenues, expenses, gains and losses that are included in comprehensive income but excluded from net income.
Litigation Costs and Reserves	Litigation Costs and Reserves Quanta records reserves when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Costs incurred for litigation are expensed as incurred. Further details are presented in Note 15.
Fair Value Measurements	Fair Value Measurements The carrying values of cash equivalents, accounts receivable, accounts payable and accrued expenses approximate fair value due to the short-term nature of these instruments. The carrying value of variable rate debt also approximates fair value. For disclosure purposes, qualifying assets and liabilities are categorized into three broad levels based on the priority of the inputs used to determine their fair values. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). All of Quanta’s cash equivalents were categorized as Level 1 assets at December 31, 2015 and 2014, as all values were based on unadjusted quoted prices for identical assets in an active market that Quanta has the ability to access. In connection with Quanta’s acquisitions, identifiable intangible assets acquired include goodwill, backlog, customer relationships, trade names, covenants not-to-compete, patented rights and developed technology. Quanta utilizes the fair value premise as the primary basis for its valuation procedures, which is a market-based approach to determine the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Quanta periodically engages the services of an independent valuation firm when a new business is acquired to assist management with this valuation process, including assistance with the selection of appropriate valuation methodologies and the development of market-based valuation assumptions. Based on these considerations, management utilizes various valuation methods, including an income approach, a market approach and a cost approach, to determine the fair value of intangible assets acquired based on the appropriateness of each method in relation to the type of asset being valued. The assumptions used in these valuation methods are analyzed and compared, where possible, to available market data, such as industry-based weighted average costs of capital and discount rates, trade name royalty rates, public company valuation multiples and recent market acquisition multiples. In accordance with its annual impairment test during the quarter ended December 31, 2015, the carrying amounts of such assets, including goodwill, were compared to their fair values. The level of inputs used for these fair value measurements is the lowest level (Level 3). Quanta uses the assistance of third party specialists to develop valuation assumptions. Quanta believes that these valuation methods appropriately represent the methods that would be used by other market participants in determining fair value. Quanta also uses fair value measurements in connection with the valuation of its investments in private company equity interests and financing instruments. These valuations require significant management judgment due to the absence of quoted market prices, the inherent lack of liquidity and the long-term nature of such assets. Typically, the initial costs of these investments are considered to represent fair market value, as such amounts are negotiated between willing market participants. On a quarterly basis, Quanta performs an evaluation of its investments to determine if an other-than-temporary decline in the value of each investment has occurred and whether the recorded amount of each investment will be realizable. If an other-than-temporary decline in the value of an investment occurs, a fair value analysis would be performed to determine the degree to which the investment was impaired and a corresponding charge to earnings would be recorded during the period. These types of fair market value assessments are similar to other nonrecurring fair value measures used by Quanta, which include the use of significant judgment and available relevant market data. Such market data may include observations of the valuation of comparable companies, risk adjusted discount rates and an evaluation of the expected performance of the underlying portfolio asset, including historical and projected levels of profitability or cash flows. In addition, a variety of additional factors may be reviewed by management, including, but not limited to, contemporaneous financing and sales transactions with third parties, changes in market outlook and the third-party financing environment.
Adoption of New Accounting Pronouncements	Adoption of New Accounting Pronouncements In April 2014, the Financial Accounting Standards Board (FASB) issued an update that changes the requirement for reporting discontinued operations. A disposal of a component of an entity or a group of components of an entity is required to be reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results when the entity or group of components of an entity meets the criteria to be classified as held for sale or when it is disposed of by sale or other than by sale. The update also requires additional disclosures about discontinued operations, a disposal of an individually significant component of an entity that does not qualify for discontinued operations presentation in the financial statements, and an entity’s significant continuing involvement with a discontinued operation. Quanta adopted this guidance effective January 1, 2015 and has incorporated the new requirements into its presentation of the disposition of its fiber optic licensing operations as discontinued operations. In November 2015, the FASB issued an update that requires deferred tax assets and liabilities, as well as related valuation allowances, to be classified as non-current in a classified balance sheet. For public business entities, the update is effective for financial statements issued for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early application is permitted as of the beginning of an interim or annual reporting period. Quanta adopted this guidance during the quarter ended December 31, 2015, and the guidance has been applied retrospectively to all periods presented. As a result of adopting this guidance, Quanta recorded a reduction to prepaid expenses and other current assets of $49.2 million, a reduction to other assets, net of $0.2 million, a reduction to accounts payable and accrued expenses of $31.0 million and a reduction to deferred tax liabilities of $18.4 million as of December 31, 2014. Additionally, there was a $9.0 million reduction to current assets of discontinued operations and a corresponding reduction to non-current liabilities of discontinued operations as of December 31, 2014. There was no impact on results of operations or cash flows as a result of the adoption of this guidance.
Accounting Standards Not Yet Adopted	Accounting Standards Not Yet Adopted In May 2014, the FASB issued an update that supersedes most current revenue recognition guidance as well as some cost recognition guidance. The update requires that an entity recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This update also requires new qualitative and quantitative disclosures about the nature, amount, timing and uncertainty of revenues and cash flows arising from customer contracts, including significant judgments and changes in judgments, information about contract balances and performance obligations, and assets recognized from costs incurred to obtain or fulfill a contract. On July 9, 2015, the FASB affirmed its proposal to defer the effective date until fiscal years beginning on or after December 15, 2017. The guidance can be applied on a full retrospective or modified retrospective basis whereby the entity records a cumulative effect of initially applying this update at the date of initial application. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and is planning to adopt this guidance effective January 1, 2018. In August 2014, the FASB issued guidance to address the diversity in practice in determining when there is substantial doubt about an entity’s ability to continue as a going concern and when and how an entity must disclose certain relevant conditions and events. This update requires an entity to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern for a period of one year after the date that the financial statements are issued (or available to be issued). If such conditions or events exist, an entity should disclose that there is substantial doubt about the entity’s ability to continue as a going concern for a period of one year after the date that the financial statements are issued (or available to be issued), along with the principal conditions or events that raise substantial doubt, management’s evaluation of the significance of those conditions or events in relation to the entity’s ability to meet its obligations and management’s plans that are intended to mitigate those conditions or events. The guidance is effective for annual and interim periods ending after December 15, 2016. This guidance will impact the disclosure and presentation of any substantial doubt by Quanta about its ability to continue as a going concern, if such substantial doubt were to exist. Quanta will adopt this guidance effective January 1, 2017. In February 2015, the FASB issued an update which amends existing consolidation guidance, including amending the guidance related to determining whether an entity is a variable interest entity. The update is effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The guidance may be applied using a modified retrospective approach whereby the entity records a cumulative effect of adoption at the beginning of the fiscal year of initial application. A reporting entity may also apply the amendments on a full retrospective basis. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In April 2015, the FASB issued an update that requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts and premiums. The standard is effective for interim and annual reporting periods beginning after December 15, 2015, although early adoption is permitted. The update is required to be adopted retroactively for all periods presented. In August 2015, the FASB issued another update that states that the Securities Exchange Commission (SEC) staff would not object to an entity deferring and presenting debt issuance costs as an asset and subsequently amortizing the deferred debt issuance costs ratably over the term of the line-of-credit arrangement, regardless of whether there are any outstanding borrowings on the line-of-credit arrangement. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In April 2015, the FASB issued an update that provides guidance to customers about whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, the customer should account for the arrangement as a service contract. The standard is effective for interim and annual reporting periods beginning after December 15, 2015. An entity can elect to adopt the amendments either prospectively to all arrangements entered into or materially modified after the effective date or retrospectively. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In July 2015, the FASB issued an update that requires inventory to be measured at the lower of either cost or net realizable value. When evidence exists that the net realizable value of inventory is lower than its cost, the difference will be recognized as a loss in earnings in the period in which it occurs. The update is required to be adopted prospectively and is effective for interim and annual reporting periods beginning after December 15, 2016, although early adoption is permitted. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and will adopt this guidance by January 1, 2017. In September 2015, the FASB issued an update that requires an acquiring company to recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which such adjustments are determined. An acquiring company must record any effect on earnings from changes in depreciation or amortization or other income effects, calculated as if the accounting had been completed at the acquisition date. The acquiring company must also present separately on the face of the income statement or disclose in the notes the amount recorded in current-period earnings that would have been recorded in previous reporting periods if the adjustment had been recognized as of the acquisition date. The standard is effective for interim and annual reporting periods beginning after December 15, 2015. The update is required to be adopted prospectively to adjustments that occur after the effective date with earlier application permitted for financial statements that have not yet been issued. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016. In January 2016, the FASB issued an update that addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. The new standard is effective for interim and annual periods beginning after December 15, 2017. Early adoption is permitted for financial statements of fiscal years or interim periods that have not been previously issued. Quanta is evaluating the impact of the new standard on its consolidated financial statements and will adopt the new standard by January 1, 2018. In February 2016, the FASB issued an update that requires companies that lease assets to recognize on the balance sheet the assets and liabilities for the rights and obligations created by those assets. The new standard is effective for interim and annual periods beginning after December 15, 2018. Early adoption is permitted for financial statements of fiscal years or interim periods that have not been previously issued. Quanta is evaluating the impact of the new standard on its consolidated financial statements and will adopt the new standard by January 1, 2019.
Repurchase of Common Stock	During the third quarter of 2015, Quanta’s board of directors approved a new stock repurchase program authorizing Quanta to purchase, from time to time through February 28, 2017, up to $1.25 billion of its outstanding common stock (the 2015 Repurchase Program). Repurchases under the 2015 Repurchase Program can be made in open market or privately negotiated transactions, including pursuant to an accelerated share repurchase arrangement, an issuer repurchase plan or otherwise, at management’s discretion, based on market and business conditions, applicable contractual and legal requirements and other factors. The 2015 Repurchase Program does not obligate Quanta to acquire any specific amount of common stock and may be modified or terminated by Quanta’s board of directors at any time at its sole discretion and without notice. On August 7, 2015, Quanta entered into an accelerated share repurchase arrangement (the ASR) to repurchase $750.0 million of its common stock under the 2015 Repurchase Program. Under the terms of the ASR, Quanta paid $750.0 million to JPMorgan Chase Bank, National Association, London Branch (JPMorgan) and initially received 25.7 million shares of its common stock. The fair market value of these 25.7 million shares at the time of delivery was approximately $600.0 million, and the repurchased shares and the related cost to acquire them were accounted for as an adjustment to the balance of treasury stock during the quarter ended September 30, 2015, reducing the weighted-average number of basic and diluted common shares used to calculate Quanta’s earnings per share for the year ended December 31, 2015. The $150.0 million remaining under the ASR was recorded as an adjustment to additional paid-in capital (APIC) during the quarter ended September 30, 2015 and will be reclassified from APIC to treasury stock upon final settlement of the ASR. The final number of shares that Quanta will repurchase under the ASR will be based on a volume-weighted average share price of its common stock during the term of the ASR, minus a discount and subject to other adjustments pursuant to the terms and conditions of the ASR. Final settlement of the ASR is scheduled to occur in the second quarter of 2016, but the ASR may be terminated early or extended in certain circumstances. At settlement, based on the final volume-weighted average share price, Quanta may be entitled to receive additional shares of its common stock from JPMorgan or, under certain circumstances, may be required to deliver shares or make a cash payment (at its option) to JPMorgan. In addition to the initial share delivery under the ASR, during the third and fourth quarters of 2015, Quanta repurchased 19.2 million shares of its common stock at a cost of $449.9 million in the open market under the 2015 Repurchase Program. During the fourth quarter of 2013, Quanta’s board of directors approved a stock repurchase program authorizing Quanta to purchase, from time to time through December 31, 2016, up to $500.0 million of its outstanding common stock (the 2013 Repurchase Program). During the year ended December 31, 2015, Quanta repurchased 14.4 million shares of its common stock at a cost of $406.5 million in the open market under the 2013 Repurchase Program. During the third quarter of 2015, Quanta completed the 2013 Repurchase Program. During the year ended December 31, 2015, Quanta repurchased a total of 59.3 million shares valued at $1.46 billion pursuant to both the 2013 Repurchase Program and the 2015 Repurchase Program. During the year ended December 31, 2014, Quanta repurchased approximately 3.0 million shares of its common stock under the 2013 Repurchase Program at a cost of $93.5 million. During the year ended December 31, 2013, Quanta did not repurchase any of its common stock. The shares and the related cost to acquire them have been accounted for as an adjustment to the balance of treasury stock.
Segment Reporting	Quanta presents its operations under two reportable segments: (1) Electric Power Infrastructure Services and (2) Oil and Gas Infrastructure Services. This structure is generally based on the broad end-user markets for Quanta’s services. See Note 1 for additional information regarding Quanta’s reportable segments. Quanta’s segment results are derived from the types of services provided across its operating units in each of the end user markets described above. Quanta’s entrepreneurial business model allows each of its operating units to serve the same or similar customers and to provide a range of services across end user markets. Quanta’s operating units are organized into one of two internal divisions, namely, the Electric Power Infrastructure Services Division and the Oil and Gas Infrastructure Services Division. These internal divisions are closely aligned with the reportable segments described above based on their operating units’ predominant type of work. Reportable segment information, including revenues and operating income by type of work, is gathered from each operating unit for the purpose of evaluating segment performance in support of Quanta’s market strategies. These classifications of Quanta’s operating unit revenues by type of work for segment reporting purposes can at times require judgment on the part of management. Quanta’s operating units may perform joint infrastructure service projects for customers in multiple industries, deliver multiple types of network services under a single customer contract or provide service across industries, for example, joint trenching projects to install distribution lines for electric power and natural gas customers. In addition, Quanta’s integrated operations and common administrative support at each of its operating units require that certain allocations of shared and indirect costs, such as facility costs and indirect operating expenses, including depreciation and general and administrative costs, be made to determine operating segment profitability. Corporate costs, such as payroll and benefits, employee travel expenses, facility costs, professional fees, acquisition costs and amortization related to certain intangible assets are not allocated.

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Significant Estimates Used by Management in Determining Fair Values of Company's Reporting Units	The following table presents the significant estimates used by management in determining the fair values of Quanta’s reporting units at December 31, 2015, 2014 and 2013: 2015 2014 2013 Years of cash flows before terminal value 5 5 5 Discount rates 12% to 16% 12% to 14% 12% to 14% EBITDA multiples 5.0 to 6.5 5.0 to 6.0 5.0 to 8.0 Weighting of three approaches: Discounted cash flows 70% 70% 70% Market multiple 15% 15% 15% Market capitalization 15% 15% 15%

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2015
Discontinued Operations [Member]
Summary of Financial Information for Discontinued Operations	The following represents a reconciliation of the major classes of line items constituting income from discontinued operations related to Quanta’s fiber optic licensing operations (in thousands): Year Ended December 31, 2015 2014 2013 Major classes of line items constituting pretax income from fiber optic licensing operations: Revenues $ 59,998 $ 104,021 $ 111,265 Expenses: Cost of services (including depreciation) 24,748 39,295 42,745 Selling, general and administrative expenses 12,047 16,561 15,941 Amortization of intangible assets 963 1,650 1,650 Other income (expense) items that are not major 10 3 — Net income before taxes of discontinued operations related to fiber optic licensing operations related to major classes of income before taxes 22,250 46,518 50,929 Pretax gain on the disposal of the fiber optic licensing operations 271,833 — — Total pretax gain on fiber optic licensing operations 294,083 46,518 50,929 Provision for income taxes related to fiber optic licensing operations 103,462 18,401 21,065 Net income from discontinued operations related to fiber optic licensing operations 190,621 28,117 29,864 Net loss from discontinued operations related to telecommunication operations — $ (627 ) $ — Net income from discontinued operations as presented in the statements of operations $ 190,621 $ 27,490 $ 29,864 The following represents a reconciliation of the carrying amounts of major classes of assets and liabilities of fiber optic licensing operations (in thousands): December 31, December 31, Carrying amounts of major classes of assets included as part of fiber optic licensing operations: Current assets: Accounts receivable $ — $ 11,429 Prepaid expenses and other current assets — 2,258 Total current assets of fiber optic licensing operations $ — $ 13,687 Non-current assets: Property and equipment $ — $ 380,554 Other intangible assets, net of accumulated amortization — 17,009 Goodwill — 334,790 Total major classes of non-current assets of fiber optic licensing operations — 732,353 Other non-current assets included in fiber optic licensing operations — 6,709 Total non-current assets of fiber optic licensing operations $ — $ 739,062 Carrying amounts of major classes of liabilities of fiber optic licensing operations: Current liabilities: Accounts payable and accrued expenses $ 15,313 $ 21,091 Total current liabilities of fiber optic licensing operations $ 15,313 $ 21,091 Non-current liabilities: Deferred income taxes $ — $ 57,108 Long-term deferred revenue — 48,231 Total major classes of non-current liabilities of fiber optic licensing operations — 105,339 Other non-current liabilities of fiber optic licensing operations — 193 Total non-current liabilities of fiber optic licensing operations $ — $ 105,532

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Business Acquisition Purchase Price Allocation Assets Acquired and Liabilities Assumed	This allocation requires a significant use of estimates and is based on information that was available to management at the time these consolidated financial statements were prepared (in thousands). 2015 2014 Consideration: Value of Quanta common stock and exchangeable shares issued $ 10,127 $ 134,538 Cash paid or payable 110,428 279,533 Contingent consideration 1,001 — Fair value of total consideration transferred or estimated to be transferred $ 121,556 $ 414,071 Current assets $ 35,188 $ 172,121 Property and equipment 44,140 159,186 Other assets 4 3,501 Identifiable intangible assets 24,987 96,302 Current liabilities (24,633 ) (145,646 ) Deferred tax liabilities, net (5,131 ) (32,856 ) Other long-term liabilities (5,606 ) (4,926 ) Non-controlling interests 747 — Total identifiable net assets 69,696 247,682 Goodwill 51,860 166,389 $ 121,556 $ 414,071
Estimated Fair Values of Identifiable Intangible Assets and Related Weighted Average Amortization	The following table summarizes the estimated fair values of identifiable intangible assets and the related weighted average amortization periods by type as of the respective acquisition dates for the 2015 acquisitions (in thousands, except for weighted average amortization periods, which are in years). Estimated Weighted Average Customer relationships $ 16,257 13.7 Backlog 2,552 1.3 Trade names 4,002 8.8 Non-compete agreements 2,176 5.0 Total intangible assets subject to amortization acquired in 2015 acquisitions $ 24,987 10.9
Unaudited Supplemental Pro Forma Results of Operations	Future results may vary significantly from the results reflected in the following pro forma financial information because of future events and transactions, as well as other factors (in thousands, except per share amounts): Year Ended December 31, 2015 2014 2013 Revenues $ 7,635,932 $ 8,476,584 $ 7,629,310 Gross profit $ 939,452 $ 1,248,827 $ 1,185,691 Selling, general and administrative expenses $ 600,057 $ 745,321 $ 563,877 Amortization of intangible assets $ 36,479 $ 47,777 $ 50,755 Net income from continuing operations $ 135,467 $ 303,772 $ 451,399 Net income from continuing operations attributable to common stock $ 124,550 $ 285,404 $ 432,011 Earnings per share from continuing operations attributable to common stock — basic and diluted $ 0.64 $ 1.28 $ 1.95

Goodwill and Other Intangible31

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Changes in Quanta's Goodwill	A summary of changes in Quanta’s goodwill is as follows (in thousands): Electric Power Infrastructure Oil and Gas Services Division Total Goodwill balance at December 31, 2013 $ 1,168,084 $ 277,843 $ 1,445,927 Goodwill acquired during 2014 71,517 102,968 174,485 Foreign currency translation adjustments (16,377 ) (7,340 ) (23,717 ) Goodwill balance at December 31, 2014 1,223,224 373,471 1,596,695 Goodwill acquired during 2015 31,224 20,636 51,860 Purchase price allocation adjustments 750 (8,867 ) (8,117 ) Goodwill impaired during 2015 — (39,826 ) (39,826 ) Foreign currency translation adjustments (28,953 ) (19,001 ) (47,954 ) Balance at December 31, 2015: Goodwill $ 1,226,245 $ 366,306 $ 1,592,551 Accumulated impairment — (39,893 ) (39,893 ) $ 1,226,245 $ 326,413 $ 1,552,658
Other Intangible Assets	Quanta’s intangible assets subject to amortization and the remaining weighted average amortization periods related to such assets were as follows (in thousands except for weighted average amortization periods, which are in years): As of December 31, 2015 As of December 31, 2014 As of December 31, 2015 Intangible Assets Accumulated Amortization Intangible Assets, Net Intangible Assets Accumulated Amortization Intangible Assets, Net Remaining Customer relationships $ 236,731 $ (90,840 ) $ 145,891 $ 235,851 $ (63,764 ) $ 172,087 9.7 Backlog 130,818 (126,954 ) 3,864 133,704 (122,265 ) 11,439 0.7 Trade names 51,192 (9,525 ) 41,667 49,664 (6,278 ) 43,386 18.6 Non-compete agreements 28,560 (23,507 ) 5,053 27,659 (21,365 ) 6,294 3.5 Patented rights and developed technology 22,447 (13,848 ) 8,599 22,073 (11,695 ) 10,378 4.0 Total intangible assets subject to amortization $ 469,748 $ (264,674 ) $ 205,074 $ 468,951 $ (225,367 ) $ 243,584 10.9
Estimated Future Aggregate Amortization Expense of Intangible Assets	The estimated future aggregate amortization expense of intangible assets subject to amortization as of December 31, 2015 is set forth below (in thousands): For the Fiscal Year Ending December 31, 2016 $ 28,172 2017 22,758 2018 22,015 2019 21,219 2020 20,103 Thereafter 90,807 Total $ 205,074

Per Share Information (Tables)

Per Share Information (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Basic and Diluted Earnings Per Share	The amounts used to compute the basic and diluted earnings per share for the years ended December 31, 2015, 2014 and 2013 are illustrated below (in thousands): Year Ended December 31, 2015 2014 2013 Amounts attributable to common stock: Net income from continuing operations $ 120,286 $ 269,224 $ 372,057 Net income from discontinued operations 190,621 27,490 29,864 Net income attributable to common stock $ 310,907 $ 296,714 $ 401,921 Weighted average shares: Weighted average shares outstanding for basic earnings per share 195,113 219,668 214,929 Effect of dilutive stock options 7 22 49 Weighted average shares outstanding for diluted earnings per share 195,120 219,690 214,978

Detail of Certain Balance She33

Detail of Certain Balance Sheet Accounts (Tables)	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
Current and Long-Term Allowance for Doubtful Accounts	Activity in Quanta’s current and long-term allowance for doubtful accounts consisted of the following (in thousands): December 31, 2015 2014 Balance at beginning of year $ 6,174 $ 5,215 Charged to bad debt expense and provision for long-term contract receivable 224 103,871 Deductions for uncollectible receivables written off, net of recoveries (1,172 ) (102,912 ) Balance at end of year $ 5,226 $ 6,174
Contracts in Progress	Contracts in progress were as follows (in thousands): December 31, 2015 2014 Costs incurred on contracts in progress $ 5,725,078 $ 6,603,351 Estimated earnings, net of estimated losses 756,974 1,111,657 6,482,052 7,715,008 Less — Billings to date (6,563,537 ) (7,675,674 ) $ (81,485 ) $ 39,334 Costs and estimated earnings in excess of billings on uncompleted contracts $ 317,745 $ 290,447 Less — Billings in excess of costs and estimated earnings on uncompleted contracts (399,230 ) (251,113 ) $ (81,485 ) $ 39,334
Property and Equipment	Property and equipment consisted of the following (in thousands): Estimated Useful Lives in Years December 31, 2015 2014 Land N/A $ 41,428 $ 40,657 Buildings and leasehold improvements 5-30 116,697 93,042 Operating equipment and vehicles 5-25 1,517,630 1,459,409 Office equipment, furniture and fixtures and information technology systems 3-15 137,670 119,529 Construction work in progress N/A 43,806 38,496 1,857,231 1,751,133 Less — Accumulated depreciation and amortization (755,272 ) (651,559 ) Property and equipment, net $ 1,101,959 $ 1,099,574
Accounts Payable and Accrued Expenses	Accounts payable and accrued expenses consisted of the following (in thousands): December 31, 2015 2014 Accounts payable, trade $ 452,295 $ 477,370 Accrued compensation and related expenses 159,045 164,777 Accrued insurance, current portion 61,327 49,309 Deferred revenues, current portion 8,010 13,082 Income and franchise taxes payable 3,923 20,946 Other accrued expenses 97,534 99,747 $ 782,134 $ 825,231

Debt Obligations (Tables)

Debt Obligations (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Long-term Debt Obligations	Quanta’s long-term debt obligations consisted of the following (in thousands): December 31, 2015 2014 Borrowings under credit facility $ 466,850 $ 68,793 Other long-term debt, interest rates ranging from 3.4% to 4.3% 5,401 6,370 Capital leases, interest rates ranging from 2.5% to 6.2% 5,351 1,146 Total long-term debt obligations 477,602 76,309 Less — Current maturities of long-term debt 2,238 3,820 Total long-term debt obligations, net of current maturities $ 475,364 $ 72,489
Current Maturities of Long-Term Debt and Short-Term Borrowings	Quanta’s current maturities of long-term debt and short-term borrowings consisted of the following (in thousands): December 31, 2015 2014 Short-term borrowings $ 4,829 $ 5,056 Current maturities of long-term debt 2,238 3,820 Current maturities of long-term debt and short-term borrowings $ 7,067 $ 8,876
Information on Borrowings under Current and Prior Credit Facility and Applicable Interest Rates	of credit or bank guarantees. Information on borrowings under Quanta’s credit facility and the applicable interest rates during the years ended December 31, 2015 and 2014 is as follows (dollars in thousands): Year Ended December 31, 2015 2014 2013 Maximum amount outstanding during the period $ 606,753 $ 130,856 $ 161,920 Average daily amount outstanding under the credit facility $ 258,815 $ 29,814 $ 14,482 Weighted-average interest rate 1.79 % 2.71 % 2.12 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Components of Income (Loss) Before Income Taxes	The components of income (loss) from continuing operations before income taxes were as follows (in thousands): Year Ended December 31, 2015 2014 2013 Income (loss) from continuing operations before income taxes: Domestic $ 244,955 $ 263,357 $ 472,816 Foreign (16,280 ) 163,242 115,504 Total $ 228,675 $ 426,599 $ 588,320
Provision for Income Taxes	The components of the provision for income taxes for continuing operations were as follows (in thousands): Year Ended December 31, 2015 2014 2013 Current: Federal $ 85,830 $ 67,430 $ 164,397 State 9,783 8,693 20,998 Foreign 21,262 39,978 37,193 Total current tax provision 116,875 116,101 222,588 Deferred: Federal (5,247 ) 11,507 (22,611 ) State 917 2,232 (2,540 ) Foreign (15,073 ) 9,167 (562 ) Total deferred tax provision (benefit) (19,403 ) 22,906 (25,713 ) Total provision for income taxes from continuing operations $ 97,472 $ 139,007 $ 196,875
Effective Income Tax Rate Reconciliation	The actual income tax provision differed from the income tax provision computed by applying the U.S. federal statutory corporate rate to income from continuing operations before provision for income taxes as follows (in thousands): Year Ended December 31, 2015 2014 2013 Provision at the statutory rate $ 80,036 $ 149,697 $ 205,912 Increases (decreases) resulting from — State taxes 7,241 7,890 11,201 Foreign taxes 1,239 (13,059 ) (9,994 ) Contingency reserves, net 4,438 (650 ) (3,385 ) Production activity deduction (6,871 ) (6,033 ) (10,247 ) Employee per diems, meals and entertainment 8,727 9,817 7,888 Taxes on unincorporated joint ventures (3,838 ) (6,429 ) (6,786 ) Asset impairments 7,047 — — Other (547 ) (2,226 ) 2,286 Total provision for income taxes from continuing operations $ 97,472 $ 139,007 $ 196,875
Deferred Tax Assets and Liabilities	Deferred income taxes result from temporary differences in the recognition of income and expenses for financial reporting purposes and tax purposes. The tax effects of these temporary differences, representing deferred tax assets and liabilities, result principally from the following (in thousands): December 31, 2015 2014 Deferred income tax liabilities: Property and equipment $ (189,793 ) $ (185,007 ) Goodwill (69,059 ) (70,832 ) Other intangibles (36,565 ) (48,344 ) Other book/tax accounting method differences (61,095 ) (63,819 ) Total deferred income tax liabilities $ (356,512 ) (368,002 ) Deferred income tax assets: Accruals and reserves 25,070 20,835 Accrued insurance 75,591 64,745 Stock and incentive compensation and pension withdrawal liabilities 52,009 53,155 Net operating loss carryforwards 27,255 19,353 Other 10,894 10,194 Subtotal 190,819 168,282 Valuation allowance (16,141 ) (13,028 ) Total deferred income tax assets 174,678 155,254 Total net deferred income tax liabilities $ (181,834 ) $ (212,748 )
Net Deferred Income Tax Assets and Liabilities	The net deferred income tax assets and liabilities were comprised of the following (in thousands): December 31, 2015 2014 Deferred income taxes: Assets 4,657 3,233 Liabilities (186,491 ) (215,981 ) Total net deferred income tax liabilities $ (181,834 ) $ (212,748 )
Reconciliation of Unrecognized Tax Benefit	A reconciliation of unrecognized tax benefit balances is as follows (in thousands): December 31, 2015 2014 2013 Balance at beginning of year $ 50,668 $ 48,306 $ 50,555 Additions based on tax positions related to the current year 5,340 9,133 8,984 Additions for tax positions of prior years 292 2,438 — Reductions for tax positions of prior years (132 ) — — Reductions for audit settlements (1,345 ) — — Reductions resulting from a lapse of the applicable statute of limitations periods (282 ) (9,209 ) (11,233 ) Balance at end of year $ 54,541 $ 50,668 $ 48,306
Balances of Unrecognized Tax Benefits	The balances of unrecognized tax benefits, the amount of related interest and penalties and what Quanta believes to be the range of reasonably possible changes in the next 12 months are as follows (in thousands): December 31, 2015 2014 2013 Unrecognized tax benefits $ 54,541 $ 50,668 $ 48,306 Portion that, if recognized, would reduce tax expense and effective tax rate 48,312 42,952 40,029 Accrued interest on unrecognized tax benefits 8,750 6,304 5,766 Accrued penalties on unrecognized tax benefits 673 697 99 Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months $ 0 to $27,485 $ 0 to $10,221 $ 0 to $6,554 Portion that, if recognized, would reduce tax expense and effective tax rate $ 0 to $24,009 $ 0 to $8,484 $ 0 to $4,816

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Restricted Stock and RSU to be Settled in Common Stock Activity	A summary of the activity for restricted stock and RSUs to be settled in common stock for the year ended December 31, 2015 is as follows (shares in thousands): Shares Weighted Average Grant Date Fair Value (Per share) Unvested at January 1, 2015 2,433 $ 31.29 Granted 1,307 $ 27.64 Vested (1,266 ) $ 28.37 Forfeited (97 ) $ 31.13 Unvested at December 31, 2015 2,377 $ 30.36

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Summary of Plan Information Relating to Participation in Multiemployer Pension Plans	Information has been presented separately for individually significant plans and in the aggregate for all other plans. Fund Employee PPA Zone Subject Contributions (in thousands) Surcharge Expiration Date 2015 2014 2015 2014 2013 National Electrical Benefit Fund 53-0181657-001 Green Green No $ 21,200 $ 20,758 $ 17,268 No Varies through Laborers National Pension Fund 75-1280827-001 Green Green No 7,671 4,227 4,681 No Varies through Pipeline Industry Pension Fund 73-6146433-001 Green Green No 6,087 6,280 4,511 No Varies through Central Pension Fund of the IUOE & Participating Employers 36-6052390-001 Green Green No 5,677 7,847 4,259 No Varies through Midwest Operating Engineers Pension Trust Fund 36-6140097-001 Yellow Yellow Yes 3,294 497 217 Yes Varies through Laborers Pension Trust Fund for Northern California 94-6277608-001 Yellow Yellow Yes 2,603 1,357 987 Yes June 2019 Eighth District Electrical Pension Fund 84-6100393-001 Green Green No 2,544 2,192 1,790 No Varies through OE Pension Trust Fund 94-6090764-001 Red Red Yes 1,264 991 902 Yes June 2016 Operating Engineers Local 324 Pension Fund 38-1900637-001 Red Red Yes 1,231 1,086 818 Yes Varies through Local 697 IBEW and Electrical Industry Pension Fund 51-6133048-001 Yellow Yellow Yes 1,066 200 — Yes May 2018 Joint Pension Local Union 164 IBEW 22-6031199-001 Yellow Yellow Yes 513 1,816 222 No May 2017 Alaska Teamster—Employer Pension Plan 92-6003463-024 Red Red Yes 513 516 241 Yes June 2017 Michigan Upper Peninsula Intrl Brotherhood of Elec Workers Pension Plan 36-3020872-001 Yellow Yellow Yes 300 1,307 299 No May 2017 All other plans 23,052 22,130 18,859 Total $ 77,015 $ 71,204 $ 55,054 Quanta’s contributions to the following individually significant plans were five percent or more of the total contributions to these plans for the periods indicated based on the Forms 5500 for these plans for the years ended December 31, 2014 and 2013. Forms 5500 were not yet available for these plans for the year ended December 31, 2015. Pension Fund Plan Years in which Quanta Five Percent or More Pipeline Industry Pension Fund 2014 and 2013 Michigan Upper Peninsula Intrl Brotherhood of Elec Workers Pension Plan 2014 and 2013 Eighth District Electrical Pension Fund 2014 and 2013 Laborers National Pension Fund 2014 and 2013 Joint Pension Local Union 164 IBEW 2014

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Outstanding Capital Commitments Associated with Investments in Unconsolidated Affiliates	As of December 31, 2015, Quanta had outstanding capital commitments associated with investments in an unconsolidated affiliate related to this project as follows (in thousands): Capital Commitments Year Ending December 31: 2016 $ 8,909 2017 (1) 31,010 2018 — 2019 22,895 Total capital commitments associated with investments in an unconsolidated affiliate related to an EPC electrical transmission project $ 62,814 (1) This amount excludes a return of capital from an unconsolidated affiliate of approximately $40.9 million that is anticipated in August 2017.
Minimum Lease Payments	The following schedule shows the future minimum lease payments under these leases as of December 31, 2015 (in thousands): Operating Leases Year Ending December 31: 2016 $ 78,971 2017 56,488 2018 42,608 2019 25,065 2020 14,290 Thereafter 17,281 Total minimum lease payments $ 234,703

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Summarized Financial Information	Summarized financial information for Quanta’s reportable segments is presented in the following table (in thousands): Year Ended December 31, 2015 2014 2013 Revenues: Electric Power Infrastructure $ 4,937,289 $ 5,302,671 $ 4,541,962 Oil and Gas Infrastructure 2,635,147 2,444,558 1,869,615 Consolidated $ 7,572,436 $ 7,747,229 $ 6,411,577 Operating income (loss) Electric Power Infrastructure $ 362,328 $ 462,985 $ 523,355 Oil and Gas Infrastructure 142,929 162,797 138,543 Corporate and non-allocated costs (267,754 ) (196,722 ) (185,899 ) Consolidated $ 237,503 $ 429,060 $ 475,999 Depreciation: Electric Power Infrastructure $ 89,150 $ 76,214 $ 64,913 Oil and Gas Infrastructure 65,315 57,414 47,050 Corporate and non-allocated costs 8,380 7,478 6,867 Consolidated $ 162,845 $ 141,106 $ 118,830

Quarterly Financial Data (Una40

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Consolidated Operating Results by Quarter	The table below sets forth the unaudited consolidated operating results by quarter for the years ended December 31, 2015 and 2014 (in thousands, except per share information). For the Three Months Ended March 31, June 30, September 30, December 31, 2015: Revenues $ 1,861,386 $ 1,872,340 $ 1,939,438 $ 1,899,272 Gross profit 237,906 227,505 235,215 223,039 Net income (loss) 58,185 49,565 218,956 (4,882 ) Net income (loss) attributable to common stock 53,484 46,109 216,388 (5,074 ) Net income (loss) from continuing operations attributable to common stock 47,689 32,007 43,176 (2,586 ) Earnings (loss) per share from continuing operations attributable to common stock — basic and diluted $ 0.22 $ 0.15 $ 0.23 $ (0.02 ) 2014: Revenues $ 1,735,448 $ 1,838,209 $ 2,145,958 $ 2,027,614 Gross profit 256,054 264,209 336,903 311,628 Net income 58,648 85,444 100,015 70,975 Net income attributable to common stock 54,408 81,082 94,648 66,576 Net income from continuing operations attributable to common stock 47,442 73,453 87,923 60,406 Earnings per share from continuing operations attributable to common stock — basic and diluted $ 0.22 $ 0.33 $ 0.40 $ 0.27

Business and Organization - Add

Business and Organization - Additional Information (Detail) $ in Millions	Aug. 04, 2015USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015EntitySegment	Dec. 31, 2014Entity	Dec. 31, 2013Entity
Organization And Description Of Business [Line Items]
Number of reportable segments | Segment			2
Number of business acquisitions			11	9	6
Electric Power Infrastructure Services Business [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			8
Electric Power Infrastructure Services Business [Member] | Canada [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			3	4
Electric Power Infrastructure Services Business [Member] | Australia [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			1	1
Electric Power Infrastructure Services Business [Member] | United States [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			4	1
Electric Power Infrastructure Services Business [Member] | United States Canada And Australia [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions					3
Oil and Gas Infrastructure Services Business [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			3
Oil and Gas Infrastructure Services Business [Member] | Canada [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			1	2
Oil and Gas Infrastructure Services Business [Member] | Australia [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			1
Oil and Gas Infrastructure Services Business [Member] | United States [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			1	1
Oil and Gas Infrastructure Services Business [Member] | United States Canada And Australia [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions					3
Fiber Optic Licensing Division [Member]
Organization And Description Of Business [Line Items]
Sales price of fiber optic licensing operations | $	$ 1,000
Net cash proceeds from sale of fiber optic licensing operations | $	$ 848
Gain on sale, Net of tax | $		$ 171

Summary of Significant Accoun42

Summary of Significant Accounting Policies - Additional Information (Detail)	Dec. 06, 2013USD ($)	Dec. 31, 2015USD ($)Reporting_Unit	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		$ 128,771,000	$ 128,771,000	$ 190,515,000	$ 488,777,000	$ 394,701,000
Cash equivalents		1,400,000	$ 1,400,000	$ 107,600,000
Number of days after accounts receivable are treated as delinquent			30 days	30 days
Number of days related to outstanding accounts receivable for analysis of the allowance for doubtful accounts			At least 90 days
Allowances for doubtful accounts on current receivable		5,226,000	$ 5,226,000	$ 6,174,000
Current retainage balances		250,100,000	250,100,000	307,300,000
Non-current retainage balances		4,500,000	4,500,000	19,600,000
Unbilled receivables		233,600,000	233,600,000	163,100,000
Depreciation expense related to property and equipment			162,845,000	141,106,000	118,830,000
Accrued capital expenditures			5,800,000	11,800,000
Property and equipment impairment		6,600,000		0	0
Debt issuance costs related to amendment			3,795,000		3,244,000
Capitalized debt issuance costs		11,400,000	11,400,000	7,600,000
Accumulated amortization of debt issuance costs		4,800,000	4,800,000	3,500,000
Amortization expense related to capitalized debt issuance costs			1,251,000	1,094,000	1,081,000
Non-cash charge for impairment of goodwill		$ 39,800,000	$ 39,826,000
Decrease in fair value of reporting units considered for impairment calculation		10.00%	10.00%
Intangible asset impairment charges		$ 12,100,000
Number of reporting units impacted impairment charge | Reporting_Unit		2
Change orders and/or claims		$ 137,200,000	$ 137,200,000	106,800,000
Total amount of unrecognized tax benefits relating to uncertain tax positions		54,541,000	54,541,000	50,668,000	48,306,000	50,555,000
Amount of unrecognized tax benefits change from year end relating to uncertain tax positions			3,900,000
Unrecognized tax benefits increase resulting from current period tax positions			5,340,000	9,133,000	8,984,000
Unrecognized tax benefits decrease resulting from settlements with taxing authorities			1,345,000
General liability insurance claims deductible			10,000,000			5,000,000
Auto liability insurance claims deductible			10,000,000			5,000,000
Worker's compensation claims per occurrence			5,000,000			5,000,000
Employer's liability claims subject to deductible per occurrence			1,000,000			$ 1,000,000
Employee health care benefit plans subject to deductible per claimant			$ 375,000
Howard Midstream Energy Partners, LLC [Member]
Summary Of Significant Accounting Policies [Line Items]
Proceeds from sale of equity ownership interest	$ 220,900,000
Gain on sale of equity ownership interest, Pre tax	$ 112,700,000
Equity ownership percentage held	31.00%
Restricted Stock Units to be Settled in Cash [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of common stock shares that may be received by RSU holder | shares			1
Investments in Joint Ventures [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		24,900,000	$ 24,900,000	19,100,000
Domestic Joint Ventures [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		11,900,000	$ 11,900,000	19,100,000
Tax Year 2010 [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Tax Examination, Year under Examination			2,010
Tax Year 2011 [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Tax Examination, Year under Examination			2,011
Tax Year 2012 [Member]
Summary Of Significant Accounting Policies [Line Items]
Income Tax Examination, Year under Examination			2,012
Domestic Bank Accounts [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		16,100,000	$ 16,100,000	127,200,000
Foreign Bank Accounts [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents		$ 112,700,000	$ 112,700,000	63,300,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment ownership		20.00%	20.00%
Annual growth rates by reporting units			(28.00%)
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months		$ 0	$ 0	$ 0	0
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment ownership		50.00%	50.00%
Annual growth rates by reporting units			54.00%
Percent change in contract estimates impact on operating results is less than this percentage			5.00%	5.00%
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months		$ 27,485,000	$ 27,485,000	$ 10,221,000	$ 6,554,000

Summary of Significant Accoun43

Summary of Significant Accounting Policies - Significant Estimates Used by Management in Determining Fair Values of Company's Reporting Units (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill Impairment Testing Assumptions [Line Items]
Years of cash flows before terminal value	5 years	5 years	5 years
Weighting of three approaches:
Discounted cash flows	70.00%	70.00%	70.00%
Market multiple	15.00%	15.00%	15.00%
Market capitalization	15.00%	15.00%	15.00%
Minimum [Member]
Goodwill Impairment Testing Assumptions [Line Items]
Discount rates	12.00%	12.00%	12.00%
EBITDA multiples	5	5	5
Maximum [Member]
Goodwill Impairment Testing Assumptions [Line Items]
Discount rates	16.00%	14.00%	14.00%
EBITDA multiples	6.5	6	8

New Accounting Pronouncements -

New Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets	$ 134,585	$ 161,024
Other assets, net	76,333	78,964
Accounts payable and accrued expenses	782,134	825,231
Deferred income taxes	$ 186,491	215,981
Current assets of discontinued operations		13,687
Non-current liabilities of discontinued operations		105,532
Adoption of New Accounting Pronouncements, Effects [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Prepaid expenses and other current assets		(49,200)
Other assets, net		(200)
Accounts payable and accrued expenses		(31,000)
Deferred income taxes		(18,400)
Current assets of discontinued operations		(9,000)
Non-current liabilities of discontinued operations		$ (9,000)

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Detail) - USD ($) $ in Thousands	Aug. 04, 2015	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Telecommunications Operations [Member]
Discontinued Operations [Line Items]
Legal fees				$ 1,000
Legal fees, net of tax impact				$ 600
Fiber Optic Licensing Division [Member]
Discontinued Operations [Line Items]
Sales price of fiber optic licensing operations	$ 1,000,000
Net cash proceeds from sale of fiber optic licensing operations	$ 848,000
Gain on disposal of discontinued operations before taxes		$ 272,000	$ 271,833
Tax amount from gain loss of disposal of discontinued operations		101,000
Gain on sale, Net of tax		$ 171,000

Discontinued Operations - Summa

Discontinued Operations - Summary of Financial Information for Fiber Optic Licensing Operations (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Discontinued Operations, Disposed of by Sale
Net income (loss) from discontinued operation		$ 190,621	$ 27,490	$ 29,864
Fiber Optic Licensing Division [Member]
Discontinued Operations, Disposed of by Sale
Revenues		59,998	104,021	111,265
Cost of services (including depreciation)		24,748	39,295	42,745
Selling, general and administrative expenses		12,047	16,561	15,941
Amortization of intangible assets		963	1,650	1,650
Other income (expense) items that are not major		10	3
Income (loss) from discontinued operations before taxes		22,250	46,518	50,929
Gain on disposal of discontinued operations before taxes	$ 272,000	271,833
Total pretax gain on fiber optic licensing operations		294,083	46,518	50,929
Provision for income taxes		103,462	18,401	21,065
Net income (loss) from discontinued operation		$ 190,621	28,117	$ 29,864
Telecommunications Operations [Member]
Discontinued Operations, Disposed of by Sale
Net income (loss) from discontinued operation			$ (627)

Discontinued Operations - Recon

Discontinued Operations - Reconciliation of Carrying Amounts of Major Classes of Assets and Liabilities of Fiber Optic Licensing Operations (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Accounts receivable		$ 11,429
Prepaid expenses and other current assets		2,258
Total current assets of fiber optic licensing operations		13,687
Non-current assets:
Property and equipment		380,554
Other intangible assets, net of accumulated amortization		17,009
Goodwill		334,790
Total major classes of non-current assets of fiber optic licensing operations		732,353
Other non-current assets included in fiber optic licensing operations		6,709
Total non-current assets of fiber optic licensing operations		739,062
Current liabilities:
Accounts payable and accrued expenses	$ 15,313	21,091
Total current liabilities of fiber optic licensing operations	$ 15,313	21,091
Non-current liabilities:
Deferred income taxes		57,108
Long-term deferred revenue		48,231
Total major classes of non-current liabilities of fiber optic licensing operations		105,339
Other non-current liabilities of fiber optic licensing operations		193
Total non-current liabilities of fiber optic licensing operations		$ 105,532

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Entityshares	Dec. 31, 2014USD ($)Entityshares	Dec. 31, 2013USD ($)Entityshares
Business Acquisition [Line Items]
Aggregate consideration for acquisitions	$ 110,428	$ 279,533	$ 341,100
Value of Quanta common stock and exchangeable shares issued	10,127	$ 134,500	$ 88,900
Contingent consideration	$ 1,001
Number of business acquisitions | Entity	11	9	6
Goodwill acquired	$ 51,860	$ 174,485
Fair value of accounts receivable acquired	20,600	117,200
Goodwill expected to be deductible for income tax	33,900	43,500
Income (loss) from continuing operations before income taxes	228,675	426,599	$ 588,320
2015 Acquisitions [Member]
Business Acquisition [Line Items]
Net tangible assets acquired	44,700
Goodwill acquired	51,860
Other intangible assets, acquired	25,000
Revenues	104,600	314,100	251,300
Income (loss) from continuing operations before income taxes	300	3,400	$ 18,200
Acquisition costs	$ 3,600	$ 11,600
Common Stock [Member]
Business Acquisition [Line Items]
Number of shares granted for acquired companies | shares	461,037	686,382	3,547,482
Canadian Subsidiaries [Member] | Exchangeable Shares [Member]
Business Acquisition [Line Items]
Number of shares granted for acquired companies | shares		3,825,971
Series G Preferred Stock [Member]
Business Acquisition [Line Items]
Number of shares granted for acquired companies | shares		1
Series G Preferred Stock [Member] | Canadian Subsidiaries [Member] | Exchangeable Shares [Member]
Business Acquisition [Line Items]
Number of shares granted for acquired companies | shares		899,858
Electric Power Infrastructure Services Business [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	8
Electric Power Infrastructure Services Business [Member] | United States [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	4	1
Electric Power Infrastructure Services Business [Member] | Australia [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	1	1
Electric Power Infrastructure Services Business [Member] | Canada [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	3	4
Oil and Gas Infrastructure Services Business [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	3
Oil and Gas Infrastructure Services Business [Member] | United States [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	1	1
Oil and Gas Infrastructure Services Business [Member] | Australia [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	1
Oil and Gas Infrastructure Services Business [Member] | Canada [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	1	2
Electric Power Division [Member]
Business Acquisition [Line Items]
Goodwill acquired	$ 31,224	$ 71,517	$ 112,500
Oil and Gas Infrastructure Division [Member]
Business Acquisition [Line Items]
Goodwill acquired	$ 20,636	$ 102,968	$ 143,300

Acquisitions - Business Acquisi

Acquisitions - Business Acquisition Purchase Price Allocation Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Value of Quanta common stock and exchangeable shares issued	$ 10,127	$ 134,500	$ 88,900
Cash paid or payable	110,428	279,533	341,100
Contingent consideration	1,001
Goodwill	1,552,658	1,596,695	$ 1,445,927
All Acquisitions [Member]
Business Acquisition [Line Items]
Value of Quanta common stock and exchangeable shares issued	10,127	134,538
Cash paid or payable	110,428	279,533
Contingent consideration	1,001
Fair value of total consideration transferred or estimated to be transferred	121,556	414,071
Current assets	35,188	172,121
Property and equipment	44,140	159,186
Other assets	4	3,501
Identifiable intangible assets	24,987	96,302
Current liabilities	(24,633)	(145,646)
Deferred tax liabilities, net	(5,131)	(32,856)
Other long-term liabilities	(5,606)	(4,926)
Non-controlling interests	747
Total identifiable net assets	69,696	247,682
Goodwill	51,860	166,389
Fair value of total consideration transferred	$ 121,556	$ 414,071

Acquisitions - Estimated Fair V

Acquisitions - Estimated Fair Values of Identifiable Intangible Assets and Related Weighted Average Amortization (Detail) - Acquisitions [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 24,987
Weighted Average Amortization Period at Acquisition Date	10 years 10 months 24 days
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 16,257
Weighted Average Amortization Period at Acquisition Date	13 years 8 months 12 days
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 2,552
Weighted Average Amortization Period at Acquisition Date	1 year 3 months 18 days
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 4,002
Weighted Average Amortization Period at Acquisition Date	8 years 9 months 18 days
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 2,176
Weighted Average Amortization Period at Acquisition Date	5 years

Acquisitions - Unaudited Supple

Acquisitions - Unaudited Supplemental Proforma Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Combinations [Abstract]
Revenues	$ 7,635,932	$ 8,476,584	$ 7,629,310
Gross profit	939,452	1,248,827	1,185,691
Selling, general and administrative expenses	600,057	745,321	563,877
Amortization of intangible assets	36,479	47,777	50,755
Net income from continuing operations	135,467	303,772	451,399
Net income from continuing operations attributable to common stock	$ 124,550	$ 285,404	$ 432,011
Earnings per share from continuing operations attributable to common stock - basic and diluted	$ 0.64	$ 1.28	$ 1.95

Goodwill and Other Intangible52

Goodwill and Other Intangible Assets - Summary of Changes in Quanta's Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill, beginning balance		$ 1,596,695	$ 1,445,927
Goodwill acquired		51,860	174,485
Purchase price allocation adjustments		(8,117)
Goodwill impaired	$ (39,800)	(39,826)
Foreign currency translation adjustments		(47,954)	(23,717)
Goodwill	1,592,551	1,592,551
Accumulated impairment	(39,893)	(39,893)
Goodwill, ending balance	1,552,658	1,552,658	1,596,695	$ 1,445,927
Electric Power Division [Member]
Goodwill [Line Items]
Goodwill, beginning balance		1,223,224	1,168,084
Goodwill acquired		31,224	71,517	112,500
Purchase price allocation adjustments		750
Foreign currency translation adjustments		(28,953)	(16,377)
Goodwill	1,226,245	1,226,245
Goodwill, ending balance	1,226,245	1,226,245	1,223,224	1,168,084
Oil and Gas Infrastructure Division [Member]
Goodwill [Line Items]
Goodwill, beginning balance		373,471	277,843
Goodwill acquired		20,636	102,968	143,300
Purchase price allocation adjustments		(8,867)
Goodwill impaired		(39,826)
Foreign currency translation adjustments		(19,001)	(7,340)
Goodwill	366,306	366,306
Accumulated impairment	(39,893)	(39,893)
Goodwill, ending balance	$ 326,413	$ 326,413	$ 373,471	$ 277,843

Goodwill and Other Intangible53

Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 469,748	$ 468,951
Accumulated Amortization	(264,674)	(225,367)
Intangible Assets, Net	$ 205,074	243,584
Remaining Weighted Average Amortization Period in Years	10 years 10 months 24 days
Customer Relationships [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 236,731	235,851
Accumulated Amortization	(90,840)	(63,764)
Intangible Assets, Net	$ 145,891	172,087
Remaining Weighted Average Amortization Period in Years	9 years 8 months 12 days
Backlog [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 130,818	133,704
Accumulated Amortization	(126,954)	(122,265)
Intangible Assets, Net	$ 3,864	11,439
Remaining Weighted Average Amortization Period in Years	8 months 12 days
Trade Names [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 51,192	49,664
Accumulated Amortization	(9,525)	(6,278)
Intangible Assets, Net	$ 41,667	43,386
Remaining Weighted Average Amortization Period in Years	18 years 7 months 6 days
Non-compete Agreements [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 28,560	27,659
Accumulated Amortization	(23,507)	(21,365)
Intangible Assets, Net	$ 5,053	6,294
Remaining Weighted Average Amortization Period in Years	3 years 6 months
Patented Rights and Developed Technology [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 22,447	22,073
Accumulated Amortization	(13,848)	(11,695)
Intangible Assets, Net	$ 8,599	$ 10,378
Remaining Weighted Average Amortization Period in Years	4 years

Goodwill and Other Intangible54

Goodwill and Other Intangible Assets - Additional Information (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)Reporting_Unit	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Intangible Assets Disclosure [Abstract]
Amortization of intangible assets		$ 34,848	$ 34,257	$ 25,865
Intangible asset impairment charges	$ 12,100
Number of reporting units impacted impairment charge | Reporting_Unit	2

Goodwill and Other Intangible55

Goodwill and Other Intangible Assets - Estimated Future Aggregate Amortization Expense of Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
2,016	$ 28,172
2,017	22,758
2,018	22,015
2,019	21,219
2,020	20,103
Thereafter	90,807
Intangible Assets, Net	$ 205,074	$ 243,584

Per Share Information - Basic a

Per Share Information - Basic and Diluted Earnings Per Share (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amounts attributable to common stock:
Net income from continuing operations	$ (2,586)	$ 43,176	$ 32,007	$ 47,689	$ 60,406	$ 87,923	$ 73,453	$ 47,442	$ 120,286	$ 269,224	$ 372,057
Net income from discontinued operations									190,621	27,490	29,864
Net income attributable to common stock	$ (5,074)	$ 216,388	$ 46,109	$ 53,484	$ 66,576	$ 94,648	$ 81,082	$ 54,408	$ 310,907	$ 296,714	$ 401,921
Weighted average shares:
Weighted average shares outstanding for basic earnings per share									195,113	219,668	214,929
Effect of dilutive stock options									7	22	49
Weighted average shares outstanding for diluted earnings per share									195,120	219,690	214,978

Detail of Certain Balance She57

Detail of Certain Balance Sheet Accounts - Current and Long-Term Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Balance at beginning of year	$ 6,174	$ 5,215
Charged to bad debt expense and provision for long-term contract receivable	224	103,871
Deductions for uncollectible receivables written off, net of recoveries	(1,172)	(102,912)
Balance at end of year	$ 5,226	$ 6,174

Detail of Certain Balance She58

Detail of Certain Balance Sheet Accounts - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2014
Condensed Balance Sheet Statements, Captions [Line Items]
Provision for long-term contract receivable	$ 49,900	$ 52,500	$ 102,460
Sunrise Powerlink Project [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Provision for long-term contract receivable			$ 102,500

Detail of Certain Balance She59

Detail of Certain Balance Sheet Accounts - Contracts in Progress (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Costs incurred on contracts in progress	$ 5,725,078	$ 6,603,351
Estimated earnings, net of estimated losses	756,974	1,111,657
Cost and estimated earnings, total	6,482,052	7,715,008
Less - Billings to date	(6,563,537)	(7,675,674)
Cost and estimated earnings, Net	(81,485)	39,334
Costs and estimated earnings in excess of billings on uncompleted contracts	317,745	290,447
Less - Billings in excess of costs and estimated earnings on uncompleted contracts	(399,230)	(251,113)
Cost and estimated earnings, Net	$ (81,485)	$ 39,334

Detail of Certain Balance She60

Detail of Certain Balance Sheet Accounts - Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Land	$ 41,428	$ 40,657
Buildings and leasehold improvements	116,697	93,042
Operating equipment and vehicles	1,517,630	1,459,409
Office equipment, furniture and fixtures and information technology systems	137,670	119,529
Construction work in progress	43,806	38,496
Property and equipment, Gross	1,857,231	1,751,133
Less - Accumulated depreciation and amortization	(755,272)	(651,559)
Property and equipment, net	$ 1,101,959	$ 1,099,574
Minimum [Member] | Buildings and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment of Estimated Useful Lives in Years	5 years
Minimum [Member] | Operating Equipment and Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment of Estimated Useful Lives in Years	5 years
Minimum [Member] | Office Equipment, Furniture and Fixtures and Information Technology Systems [Member]
Property, Plant and Equipment [Line Items]
Property and equipment of Estimated Useful Lives in Years	3 years
Maximum [Member] | Buildings and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment of Estimated Useful Lives in Years	30 years
Maximum [Member] | Operating Equipment and Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment of Estimated Useful Lives in Years	25 years
Maximum [Member] | Office Equipment, Furniture and Fixtures and Information Technology Systems [Member]
Property, Plant and Equipment [Line Items]
Property and equipment of Estimated Useful Lives in Years	15 years

Detail of Certain Balance She61

Detail of Certain Balance Sheet Accounts - Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Accounts payable, trade	$ 452,295	$ 477,370
Accrued compensation and related expenses	159,045	164,777
Accrued insurance, current portion	61,327	49,309
Deferred revenues, current portion	8,010	13,082
Income and franchise taxes payable	3,923	20,946
Other accrued expenses	97,534	99,747
Accounts payable and accrued expenses, Total	$ 782,134	$ 825,231

Debt Obligations - Long-term De

Debt Obligations - Long-term Debt Obligations (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
Borrowings under credit facility	$ 466,850	$ 68,793
Other long-term debt, interest rates ranging from 3.4% to 4.3%	5,401	6,370
Capital leases, interest rates ranging from 2.5% to 6.2%	5,351	1,146
Total long-term debt obligations	477,602	76,309
Total long-term debt obligations	477,602	76,309
Less - Current maturities of long-term debt	2,238	3,820
Total long-term debt obligations, net of current maturities	$ 475,364	$ 72,489

Debt Obligations - Long-term 63

Debt Obligations - Long-term Debt Obligations (Parenthetical) (Detail)	Dec. 31, 2015	Dec. 31, 2014
Minimum [Member] | Other Long Term Debt [Member]
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	3.40%	3.40%
Minimum [Member] | Capital Leases [Member]
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	2.50%	2.50%
Maximum [Member] | Other Long Term Debt [Member]
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	4.30%	4.30%
Maximum [Member] | Capital Leases [Member]
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	6.20%	6.20%

Debt Obligations - Current Matu

Debt Obligations - Current Maturities of Long-Term Debt and Short-Term Borrowings (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Short-term Debt [Abstract]
Short-term borrowings	$ 4,829	$ 5,056
Current maturities of long-term debt	2,238	3,820
Current maturities of long-term debt and short-term borrowings	$ 7,067	$ 8,876

Debt Obligations - Additional I

Debt Obligations - Additional Information (Detail) - USD ($)	Oct. 31, 2013	Oct. 30, 2013	Dec. 31, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Letters of credit and bank guarantees under the credit facility			$ 307,000,000
Amount borrowed under the credit facility			466,850,000	$ 68,793,000
Credit facility available for revolving loans or issuing new letters of credit			1,040,000,000
Letters Of Credit and Bank Guarantees [Member]
Line of Credit Facility [Line Items]
Letters of credit and bank guarantees under the credit facility			307,000,000
Letters Of Credit and Bank Guarantees [Member] | U S Dollar [Member]
Line of Credit Facility [Line Items]
Letters of credit and bank guarantees under the credit facility			220,000,000
Letters Of Credit and Bank Guarantees [Member] | Canadian and Australian dollars [Member]
Line of Credit Facility [Line Items]
Letters of credit and bank guarantees under the credit facility			87,000,000
Borrowings Under Credit Facility [Member]
Line of Credit Facility [Line Items]
Amount borrowed under the credit facility			466,850,000
Borrowings Under Credit Facility [Member] | U S Dollar [Member]
Line of Credit Facility [Line Items]
Amount borrowed under the credit facility			400,000,000
Borrowings Under Credit Facility [Member] | Canadian Dollars [Member]
Line of Credit Facility [Line Items]
Amount borrowed under the credit facility			66,900,000
Second Amendment [Member]
Line of Credit Facility [Line Items]
Reduction in Quanta's maximum funded debt and maximum senior debt by all cash and cash equivalents in excess of amount			$ 25,000,000
Percentage of capital stock of direct foreign subsidiaries required to secure credit agreement			65.00%
Amount of availability under the credit agreement and/or cash and cash equivalents on hand that must be present to allow for cash payments of dividends and stock repurchases			$ 100,000,000
Cross default provisions with debt instruments exceeding this amount			$ 100,000,000
Second Amendment [Member] | Excess of Federal Funds Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			0.50%
Second Amendment [Member] | Excess of Euro Currency Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.00%
First Amendment [Member]
Line of Credit Facility [Line Items]
Senior secured revolving credit facility		$ 700,000,000
Reduction in Quanta's maximum funded debt and maximum senior debt by all cash and cash equivalents in excess of amount	$ 25,000,000
First Amendment [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Commitment fee		0.20%
First Amendment [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Commitment fee		0.45%
First Amendment [Member] | Excess of Eurocurrency Rate Applicable to Domestic Borrowings Only [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		1.25%
First Amendment [Member] | Excess of Eurocurrency Rate Applicable to Domestic Borrowings Only [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		2.50%
First Amendment [Member] | Excess of Base Rate Domestic Borrowings Only [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		0.25%
First Amendment [Member] | Excess of Base Rate Domestic Borrowings Only [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		1.50%
First Amendment [Member] | Excess of Euro Currency Rate of Credit Agreement for Foreign Borrowings [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		1.25%
First Amendment [Member] | Excess of Euro Currency Rate of Credit Agreement for Foreign Borrowings [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		2.50%
First Amendment [Member] | Excess of Federal Funds Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate	0.50%
First Amendment [Member] | Excess of Euro Currency Rate [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate	1.00%
First Amendment [Member] | Standby Letters of Credit [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		1.25%
First Amendment [Member] | Standby Letters of Credit [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		2.50%
First Amendment [Member] | Performance Letters of Credit [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		0.75%
First Amendment [Member] | Performance Letters of Credit [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate		1.50%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Commitment fee			0.20%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Commitment fee			0.40%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Excess of Eurocurrency Rate Applicable to Domestic Borrowings Only [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Excess of Eurocurrency Rate Applicable to Domestic Borrowings Only [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			2.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Excess of Base Rate Domestic Borrowings Only [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			0.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Excess of Base Rate Domestic Borrowings Only [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Excess of Euro Currency Rate of Credit Agreement for Foreign Borrowings [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Excess of Euro Currency Rate of Credit Agreement for Foreign Borrowings [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			2.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Standby Letters of Credit [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Standby Letters of Credit [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			2.125%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Performance Letters of Credit [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			0.675%
Effective April 1, 2014 [Member] | Second Amendment [Member] | Performance Letters of Credit [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.275%
Prior and After April 1, 2014 [Member] | Second Amendment [Member]
Line of Credit Facility [Line Items]
Senior secured revolving credit facility			$ 1,810,000,000
Maturity date of senior secured revolving credit facility			Dec. 18, 2020
Option to increase revolving commitments under the credit agreement			$ 400,000,000
Prior and After April 1, 2014 [Member] | Second Amendment [Member] | Revolving Loans and Letter of Credit in Alternative Currencies [Member]
Line of Credit Facility [Line Items]
Senior secured revolving credit facility			600,000,000
Prior and After April 1, 2014 [Member] | Second Amendment [Member] | Swing Lines Loan [Member] | U S Dollar [Member]
Line of Credit Facility [Line Items]
Senior secured revolving credit facility			100,000,000
Prior and After April 1, 2014 [Member] | Second Amendment [Member] | Swing Lines Loan [Member] | Canadian Dollars [Member]
Line of Credit Facility [Line Items]
Senior secured revolving credit facility			50,000,000
Prior and After April 1, 2014 [Member] | Second Amendment [Member] | Swing Lines Loan [Member] | Australian Dollars [Member]
Line of Credit Facility [Line Items]
Senior secured revolving credit facility			$ 30,000,000
Prior to April 1, 2014 [Member] | Second Amendment [Member]
Line of Credit Facility [Line Items]
Commitment fee			0.20%
Prior to April 1, 2014 [Member] | Second Amendment [Member] | Excess of Eurocurrency Rate Applicable to Domestic Borrowings Only [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.25%
Prior to April 1, 2014 [Member] | Second Amendment [Member] | Excess of Base Rate Domestic Borrowings Only [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			0.25%
Prior to April 1, 2014 [Member] | Second Amendment [Member] | Excess of Euro Currency Rate of Credit Agreement for Foreign Borrowings [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.25%
Prior to April 1, 2014 [Member] | Second Amendment [Member] | Standby Letters of Credit [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			1.25%
Prior to April 1, 2014 [Member] | Second Amendment [Member] | Performance Letters of Credit [Member]
Line of Credit Facility [Line Items]
Debt Instrument Basis Spread On Variable Rate			0.75%

Debt Obligations - Information

Debt Obligations - Information on Borrowings under Current and Prior Credit Facility and Applicable Interest Rates (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Line of Credit Facility [Abstract]
Maximum amount outstanding during the period	$ 606,753	$ 130,856	$ 161,920
Average daily amount outstanding under the credit facility	$ 258,815	$ 29,814	$ 14,482
Weighted-average interest rate	1.79%	2.71%	2.12%

Income Taxes - Components of In

Income Taxes - Components of Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income (loss) from continuing operations before income taxes:
Domestic	$ 244,955	$ 263,357	$ 472,816
Foreign	(16,280)	163,242	115,504
Income from continuing operations before income taxes	$ 228,675	$ 426,599	$ 588,320

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 85,830	$ 67,430	$ 164,397
State	9,783	8,693	20,998
Foreign	21,262	39,978	37,193
Total current tax provision	116,875	116,101	222,588
Deferred:
Federal	(5,247)	11,507	(22,611)
State	917	2,232	(2,540)
Foreign	(15,073)	9,167	(562)
Total deferred tax provision (benefit)	(19,403)	22,906	(25,713)
Total provision for income taxes from continuing operations	$ 97,472	$ 139,007	$ 196,875

Income Taxes - Effective Income

Income Taxes - Effective Income Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Provision at the statutory rate	$ 80,036	$ 149,697	$ 205,912
Increases (decreases) resulting from -
State taxes	7,241	7,890	11,201
Foreign taxes	1,239	(13,059)	(9,994)
Contingency reserves, net	4,438	(650)	(3,385)
Production activity deduction	(6,871)	(6,033)	(10,247)
Employee per diems, meals and entertainment	8,727	9,817	7,888
Taxes on unincorporated joint ventures	(3,838)	(6,429)	(6,786)
Asset impairments	7,047
Other	(547)	(2,226)	2,286
Total provision for income taxes from continuing operations	$ 97,472	$ 139,007	$ 196,875

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred income tax liabilities:
Property and equipment	$ (189,793)	$ (185,007)
Goodwill	(69,059)	(70,832)
Other intangibles	(36,565)	(48,344)
Other book/tax accounting method differences	(61,095)	(63,819)
Total deferred income tax liabilities	(356,512)	(368,002)
Deferred income tax assets:
Accruals and reserves	25,070	20,835
Accrued insurance	75,591	64,745
Stock and incentive compensation and pension withdrawal liabilities	52,009	53,155
Net operating loss carryforwards	27,255	19,353
Other	10,894	10,194
Subtotal	190,819	168,282
Valuation allowance	(16,141)	(13,028)	$ (13,300)
Total deferred income tax assets	174,678	155,254
Total net deferred income tax liabilities	$ (181,834)	$ (212,748)

Income Taxes - Net Deferred Inc

Income Taxes - Net Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred income taxes:
Assets	$ 4,657	$ 3,233
Liabilities	(186,491)	(215,981)
Total net deferred income tax liabilities	$ (181,834)	$ (212,748)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes [Line Items]
Valuation allowance for deferred income tax assets	$ 16,141	$ 13,028	$ 13,300
Increase (decrease) in total valuation allowance	3,100	(300)	6,400
Tax effect of state and foreign net operating loss carryforwards	27,255	19,353
2,016	100
2,017	1,200
2,018	700
2,019	700
2,020	300
Thereafter	26,800
Valuation allowance foreign and state net operating loss carryforwards	13,900
Not provided U.S. income taxes of unremitted foreign earnings	269,800
Reduction due to expiration of certain federal and state statutes of limitations	282	9,209	11,233
Interest and penalties expense (income) in the provision for income taxes	2,400	$ 500	$ (200)
Gross Amount Before Balance Sheet Presentation Netting [Member]
Income Taxes [Line Items]
Tax effect of state and foreign net operating loss carryforwards	$ 29,800
Tax Year 2010 [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination	2,010
Tax Year 2011 [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination	2,011
Tax Year 2012 [Member]
Income Taxes [Line Items]
Income Tax Examination, Year under Examination	2,012

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefit (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 50,668	$ 48,306	$ 50,555
Additions based on tax positions related to the current year	5,340	9,133	8,984
Additions for tax positions of prior years	292	2,438
Reductions for tax positions of prior years	(132)
Reductions for audit settlements	(1,345)
Reductions resulting from a lapse of the applicable statute of limitations periods	(282)	(9,209)	(11,233)
Balance at end of year	$ 54,541	$ 50,668	$ 48,306

Income Taxes - Balances of Unre

Income Taxes - Balances of Unrecognized Tax Benefits (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized tax benefits	$ 54,541,000	$ 50,668,000	$ 48,306,000	$ 50,555,000
Portion that, if recognized, would reduce tax expense and effective tax rate	48,312,000	42,952,000	40,029,000
Accrued interest on unrecognized tax benefits	8,750,000	6,304,000	5,766,000
Accrued penalties on unrecognized tax benefits	673,000	697,000	99,000
Portion that, if recognized, would reduce tax expense and effective tax rate lower bound	0	0	0
Portion that, if recognized, would reduce tax expense and effective tax rate upper bound	24,009,000	8,484,000	4,816,000
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months	0	0	0
Maximum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months	$ 27,485,000	$ 10,221,000	$ 6,554,000

Equity - Additional Information

Equity - Additional Information (Detail) - USD ($)	Aug. 07, 2015	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity [Line Items]
Minimum number of shares that can be exchanged by exchangeable shareholders unless the number of remaining exchangeable shares registered in the name of the holder is less				50,000
Number of shares of Common stock received for each exchangeable share				1
Common stock, shares outstanding			152,907,166	152,907,166	210,819,790
Value of treasury stock acquired, cost method				$ 1,456,361,000	$ 93,482,000
Payments for repurchase of common stock				1,606,361,000	93,482,000
Amount in APIC paid in ASR for shares not received				150,000,000
Income attributable to the other joint venture members				10,900,000	18,400,000	$ 19,400,000
Carrying value of the investments held by Quanta in variable interest entities			$ 2,321,000	2,321,000	11,067,000
Non-controlling interests			$ 2,321,000	2,321,000	11,067,000
Distributions to non-controlling interests				21,228,000	$ 14,432,000	$ 17,625,000
Contributions received from a joint venture partner				2,313,000
Corporate Joint Venture [Member]
Equity [Line Items]
Contributions received from a joint venture partner				$ 2,313,000
2015 Repurchase Plan Open Market Purchases [Member]
Equity [Line Items]
Treasury stock acquired			19,200,000
Value of treasury stock acquired, cost method			$ 449,900,000
2013 Repurchase Program [Member]
Equity [Line Items]
Treasury stock acquired				14,400,000	3,000,000
Value of treasury stock acquired, cost method				$ 406,500,000	$ 93,500,000
2013 Repurchase Program [Member] | Maximum [Member]
Equity [Line Items]
Aggregate authorized amount of common stock to be repurchased			$ 500,000,000	$ 500,000,000
2015 Repurchase Program [Member] | Maximum [Member]
Equity [Line Items]
Aggregate authorized amount of common stock to be repurchased		$ 1,250,000,000
Accelerated Share Repurchase Agreement [Member]
Equity [Line Items]
Treasury stock acquired	25,700,000
Value of treasury stock acquired, cost method		600,000,000
Aggregate authorized amount of common stock to be repurchased	$ 750,000,000
Payments for repurchase of common stock	$ 750,000,000
Amount in APIC paid in ASR for shares not received		$ 150,000,000
2013 and 2015 Repurchase Program [Member]
Equity [Line Items]
Treasury stock acquired				59,300,000
Value of treasury stock acquired, cost method				$ 1,460,000,000
Common Stock [Member]
Equity [Line Items]
Exchangeable shares exchanged for common stock				449,929		409,110
Treasury stock acquired				59,251,407	2,996,278
Treasury Stock [Member]
Equity [Line Items]
Value of treasury stock acquired, cost method				$ 1,456,361,000	$ 93,482,000
Series F Preferred Stock [Member]
Equity [Line Items]
Number of preferred Stock issued to voting trust			1	1	1
Series G Preferred Stock [Member]
Equity [Line Items]
Number of preferred Stock issued to voting trust			1	1	1
Exchangeable Shares [Member]
Equity [Line Items]
Common stock, shares outstanding			6,876,042	6,876,042	7,325,971
Exchangeable shares exchanged for common stock				(449,929)		(409,110)
Series F- and Series G- Preferred Stock [Member]
Equity [Line Items]
Exchangeable stock shares outstanding			3,949,929	3,949,929
Common Stock Withheld for Settlement of Employee Tax Liabilities [Member] | Treasury Stock [Member]
Equity [Line Items]
Treasury stock acquired				365,070	352,558	379,566
Value of treasury stock acquired, cost method				$ 10,400,000	$ 12,300,000	$ 12,100,000

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash stock compensation expense	$ 36,939	$ 37,449	$ 34,381
2011 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares of common stock that may be issued	11,750,000
2007 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares of common stock that may be issued	4,000,000
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares	200,000	100,000	0
Granted, weighted average grant date fair value, per share	$ 28.16	$ 35.20
Awards vested	0
Compensation costs	$ 3,600	$ 2,400
Required performance period	3 years
Performance units vesting conditions	These performance units cliff-vest at the end of a three-year performance period based on achievement of three-year company financial performance targets and strategic initiatives established by the Compensation Committee.
Number of common shares issued in connection with performance units	0
Performance Units [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance units performance percentage	0.00%
Performance Units [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance units performance percentage	200.00%
Restricted Stock and Restricted Stock Units to be Settled in Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares	1,300,000	1,400,000	1,400,000
Granted, weighted average grant date fair value, per share	$ 27.64	$ 35.08	$ 29.37
Awards vested	1,300,000	1,100,000	1,100,000
Fair value of restricted stock, vested	$ 35,900	$ 37,500	$ 30,800
Compensation costs			4,300
Non-cash stock compensation expense	33,300	35,000	34,400
Unrecognized compensation cost, related to unvested restricted stock, total	$ 31,200
Expected weighted average period to recognize compensation cost on restricted stock and RSUs to be settled in stock (in years)	1 year 5 months 12 days
Restricted Stock and Restricted Stock Units to be Settled in Common Stock [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	2 years
Restricted Stock and Restricted Stock Units to be Settled in Common Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	3 years
Restricted Stock Units to be Settled in Cash [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares that may be received by RSU holder	1
Compensation expense related to Restricted Stock Units to be settled in cash	$ 4,000	3,900	3,100
Payments to settle liabilities under compensation plan	4,200	3,100	$ 1,800
Accrued liabilities under Compensation Plan	$ 2,700	$ 2,900
Restricted Stock Units to be Settled in Cash [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	2 years
Restricted Stock Units to be Settled in Cash [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for restricted stock and restricted stock units	3 years

Equity-Based Compensation - Sum

Equity-Based Compensation - Summary of Restricted Stock and RSU to be Settled in Common Stock Activity (Detail) - Restricted Stock and RSUs to be Settled in Common Stock [Member] shares in Thousands	12 Months Ended
	Dec. 31, 2015$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested at January 1, 2015, shares | shares	2,433
Granted, shares | shares	1,307
Vested, shares | shares	(1,266)
Forfeited, shares | shares	(97)
Unvested at December 31, 2015, shares | shares	2,377
Unvested, Weighted Average Grant Date Fair Value (Per share), Beginning of Period | $ / shares	$ 31.29
Granted, Weighted Average Grant Date Fair Value (Per share) | $ / shares	27.64
Vested, Weighted Average Grant Date Fair Value (Per share) | $ / shares	28.37
Forfeited, Weighted Average Grant Date Fair Value (Per share) | $ / shares	31.13
Unvested, Weighted Average Grant Date Fair Value (Per share), End of Period | $ / shares	$ 30.36

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Benefit Plans [Line Items]
Multiemployer defined contribution and other benefit plan contributions other than MEP DBP	$ 147,100,000	$ 129,000,000	$ 104,400,000
Contributions to the deferred compensation plan	1,000,000	300,000	0
Deferred compensation obligations included in other long-term liabilities	11,700,000	2,300,000
Deferred compensation obligations included in other long-term assets	$ 11,300,000	2,000,000
401K Plan [Member]
Employee Benefit Plans [Line Items]
Percentage of contribution by employer of each employee's contribution up to 3%	100.00%
Percentage of contribution by employer of each employee who contributes between three and six percent	50.00%
Percentage of employee contribution, lower range	3.00%
Percentage of employee contribution, high range	6.00%
Contributions to Quanta 401(k) Plan	$ 17,700,000	$ 13,900,000	$ 11,500,000
Red Zone [Member]
Employee Benefit Plans [Line Items]
Percentage Funded in this Zone	Less than 65%
Yellow Zone [Member]
Employee Benefit Plans [Line Items]
Percentage Funded in this Zone	Less than 80%
Green Zone [Member]
Employee Benefit Plans [Line Items]
Percentage Funded in this Zone	at least 80%

Employee Benefit Plans - Summar

Employee Benefit Plans - Summary of Plan Information Relating to Participation in Multiemployer Pension Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Multiemployer Plans [Line Items]
Contributions	$ 77,015	$ 71,204	$ 55,054
National Electrical Benefit Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	53-0181657-001
PPA Zone Status	Green	Green
Subject to Financial Improvement/ Rehabilitation Plan	No
Contributions	$ 21,200	$ 20,758	17,268
Surcharge Imposed	No
Expiration Date of Collective Bargaining Agreement	Varies through September 2019
Laborers National Pension Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	75-1280827-001
PPA Zone Status	Green	Green
Subject to Financial Improvement/ Rehabilitation Plan	No
Contributions	$ 7,671	$ 4,227	4,681
Surcharge Imposed	No
Expiration Date of Collective Bargaining Agreement	Varies through June 2017
Laborers National Pension Fund [Member] | Maximum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,014
Laborers National Pension Fund [Member] | Minimum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,013
Pipeline Industry Pension Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	73-6146433-001
PPA Zone Status	Green	Green
Subject to Financial Improvement/ Rehabilitation Plan	No
Contributions	$ 6,087	$ 6,280	4,511
Surcharge Imposed	No
Expiration Date of Collective Bargaining Agreement	Varies through June 2017
Pipeline Industry Pension Fund [Member] | Maximum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,014
Pipeline Industry Pension Fund [Member] | Minimum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,013
Central Pension Fund of the IUOE & Participating Employers [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	36-6052390-001
PPA Zone Status	Green	Green
Subject to Financial Improvement/ Rehabilitation Plan	No
Contributions	$ 5,677	$ 7,847	4,259
Surcharge Imposed	No
Expiration Date of Collective Bargaining Agreement	Varies through June 2017
Midwest Operating Engineers Pension Trust Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	36-6140097-001
PPA Zone Status	Yellow	Yellow
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 3,294	$ 497	217
Surcharge Imposed	Yes
Expiration Date of Collective Bargaining Agreement	Varies through June 2017
Laborers Pension Trust Fund for Northern California [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	94-6277608-001
PPA Zone Status	Yellow	Yellow
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 2,603	$ 1,357	987
Surcharge Imposed	Yes
Expiration Date of Collective Bargaining Agreement	June 2,019
Eighth District Electrical Pension Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	84-6100393-001
PPA Zone Status	Green	Green
Subject to Financial Improvement/ Rehabilitation Plan	No
Contributions	$ 2,544	$ 2,192	1,790
Surcharge Imposed	No
Expiration Date of Collective Bargaining Agreement	Varies through February 2018
Eighth District Electrical Pension Fund [Member] | Maximum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,014
Eighth District Electrical Pension Fund [Member] | Minimum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,013
OE Pension Trust Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	94-6090764-001
PPA Zone Status	Red	Red
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 1,264	$ 991	902
Surcharge Imposed	Yes
Expiration Date of Collective Bargaining Agreement	June 2,016
Operating Engineers Local 324 Pension Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	38-1900637-001
PPA Zone Status	Red	Red
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 1,231	$ 1,086	818
Surcharge Imposed	Yes
Expiration Date of Collective Bargaining Agreement	Varies through June 2017
Local 697 IBEW and Electrical Industry Pension Fund [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	51-6133048-001
PPA Zone Status	Yellow	Yellow
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 1,066	$ 200
Surcharge Imposed	Yes
Expiration Date of Collective Bargaining Agreement	May 2,018
Joint Pension Local Union 164 IBEW [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	22-6031199-001
PPA Zone Status	Yellow	Yellow
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 513	$ 1,816	222
Surcharge Imposed	No
Expiration Date of Collective Bargaining Agreement	May 2,017
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,014
Alaska Teamster Employer Pension Plan [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	92-6003463-024
PPA Zone Status	Red	Red
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 513	$ 516	241
Surcharge Imposed	Yes
Expiration Date of Collective Bargaining Agreement	June 2,017
Michigan Upper Peninsula Intrl Brotherhood of Elec Workers Pension Plan [Member]
Multiemployer Plans [Line Items]
Employer Identification Number	36-3020872-001
PPA Zone Status	Yellow	Yellow
Subject to Financial Improvement/ Rehabilitation Plan	Implemented
Contributions	$ 300	$ 1,307	299
Surcharge Imposed	No
Expiration Date of Collective Bargaining Agreement	May 2,017
Michigan Upper Peninsula Intrl Brotherhood of Elec Workers Pension Plan [Member] | Maximum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,014
Michigan Upper Peninsula Intrl Brotherhood of Elec Workers Pension Plan [Member] | Minimum [Member]
Multiemployer Plans [Line Items]
Plan years in which Quanta contributions were five percent or more of total plan contributions	2,013
All Other Plans [Member]
Multiemployer Plans [Line Items]
Contributions	$ 23,052	$ 22,130	$ 18,859

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transactions [Abstract]
Lease agreement terms	5 years
Related party lease expenses	$ 10.6	$ 8.5	$ 4.5

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Jan. 31, 2016USD ($)	Oct. 09, 2013USD ($)	Jan. 31, 2016USD ($)	Dec. 31, 2014USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)CustomerAgencykm	Dec. 31, 2014USD ($)Customer	Dec. 31, 2013USD ($)Customer	Jul. 31, 2014USD ($)	Apr. 21, 2010mi
Commitment And Contingencies [Line Items]
Outstanding capital commitment						$ 7,400,000
Rent expense related to operating leases						208,500,000	$ 161,500,000	$ 111,800,000
Maximum guaranteed residual value						$ 487,100,000
Number of customers representing ten percent or more of consolidated revenues | Customer						0	0	0
Number of customers representing ten percent or more of net position | Customer						1
Gross amount accrued for insurance claims				$ 170,200,000		$ 209,000,000	$ 170,200,000
Long-term insurance claims				130,800,000		153,500,000	130,800,000
Related insurance recoveries/receivables				9,100,000		8,600,000	9,100,000
Related insurance recoveries/receivables included in prepaid expenses and other current assets				800,000		600,000	800,000
Related insurance recoveries/receivables included in other assets net				8,300,000		8,000,000	$ 8,300,000
Letters of credit and bank guarantees under the credit facility						307,000,000
Total amount of outstanding performance bonds						2,600,000,000
Estimated cost to complete bonded projects						906,000,000
Multiemployer plan withdrawal obligation, amount suggested by Plan which is different than amount recorded by company		$ 6,900,000
Multiemployer plan withdrawal obligation complete withdrawal		4,800,000
Multiemployer plan withdrawal obligation accrued						2,100,000
Cash proceeds deposited in Escrow account		$ 2,100,000
Pre-acquisition non-U.S.tax obligations and indemnification asset amount recorded						11,400,000
Pre-acquisition non-U.S.tax obligations and indemnification liability amount recorded						$ 11,400,000
Subsequent Event [Member] | 2013 Central States Plan [Member]
Commitment And Contingencies [Line Items]
Amount of withdrawal liability	$ 4,800,000		$ 4,800,000
Payment of withdrawal liability amount	2,700,000
Alberta Power Line [Member]
Commitment And Contingencies [Line Items]
Length of electrical transmission line to be constructed under contract | km						500
Sunrise Powerlink Project [Member]
Commitment And Contingencies [Line Items]
Length of electrical transmission line to be constructed under contract | mi										117
Proceeds from customers				$ 65,000,000
Net Position [Member] | Customer Concentration Risk [Member] | Quanta's Electric Power Infrastructure Services Segment [Member]
Commitment And Contingencies [Line Items]
Concentration risk percentage						12.00%
Scenario Forecast [Member]
Commitment And Contingencies [Line Items]
Outstanding capital commitment					$ 1,300,000
June 1, 2017 [Member]
Commitment And Contingencies [Line Items]
Outstanding capital commitment						$ 6,100,000
Vehicle Fleet Committed Capital [Member]
Commitment And Contingencies [Line Items]
Estimated committed capital in next fiscal year						$ 2,300,000
Central States Plan [Member]
Commitment And Contingencies [Line Items]
Amount of withdrawal liability									$ 39,600,000
Central States Plan [Member] | Subsequent Event [Member]
Commitment And Contingencies [Line Items]
Amount of withdrawal liability	$ 32,900,000		32,900,000
Payment of withdrawal liability amount			$ 11,000,000
Minimum [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Commitment And Contingencies [Line Items]
Concentration risk percentage						10.00%	10.00%	10.00%
Minimum [Member] | Net Position [Member] | Customer Concentration Risk [Member]
Commitment And Contingencies [Line Items]
Concentration risk percentage						10.00%	10.00%
Minimum [Member] | Central States Plan [Member]
Commitment And Contingencies [Line Items]
Amount of withdrawal liability						$ 40,100,000
Maximum [Member] | Central States Plan [Member]
Commitment And Contingencies [Line Items]
Amount of withdrawal liability						$ 55,400,000
Lorenzo Benton v Telecom Network Specialists Inc [Member]
Commitment And Contingencies [Line Items]
Number of staffing Agency | Agency						29
Lorenzo Benton v Telecom Network Specialists Inc [Member] | Class Damage [Member]
Commitment And Contingencies [Line Items]
Amount sought by plaintiff						$ 16,000,000
Lorenzo Benton v Telecom Network Specialists Inc [Member] | Attorney Fees [Member]
Commitment And Contingencies [Line Items]
Amount sought by plaintiff						$ 5,000,000

Commitments and Contingencies82

Commitments and Contingencies - Outstanding Capital Commitments Associated with Investments in Unconsolidated Affiliates (Detail) - Corporate Joint Venture [Member] $ in Thousands	Dec. 31, 2015USD ($)
Other Commitments [Line Items]
Capital commitments, 2016	$ 8,909
Capital commitments, 2017	31,010
Capital commitments, 2018	0
Capital commitments, 2019	22,895
Total capital commitments associated with investments in an unconsolidated affiliate related to an EPC electrical transmission project	$ 62,814

Commitments and Contingencies83

Commitments and Contingencies - Outstanding Capital Commitments Associated with Investments in Unconsolidated Affiliates (Parenthetical) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Corporate Joint Venture [Member]
Other Commitments [Line Items]
Return of capital from unconsolidated affiliates anticipated for 2017	$ 40.9

Commitments and Contingencies84

Commitments and Contingencies - Minimum Lease Payments (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 78,971
2,017	56,488
2,018	42,608
2,019	25,065
2,020	14,290
Thereafter	17,281
Total minimum lease payments	$ 234,703

Segment Information - Additiona

Segment Information - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Segment	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2
Property and equipment	$ 1,101,959	$ 1,099,574
Canada [Member]
Segment Reporting Information [Line Items]
Percentage of foreign revenues	85.00%	82.00%	86.00%
Foreign Operations [Member]
Segment Reporting Information [Line Items]
Revenues	$ 1,540,000	$ 1,890,000	$ 1,310,000
Property and equipment	$ 317,600	$ 372,900

Segment Information - Summarize

Segment Information - Summarized Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 1,899,272	$ 1,939,438	$ 1,872,340	$ 1,861,386	$ 2,027,614	$ 2,145,958	$ 1,838,209	$ 1,735,448	$ 7,572,436	$ 7,747,229	$ 6,411,577
Operating income (loss)									237,503	429,060	475,999
Depreciation									162,845	141,106	118,830
Electric Power Infrastructure [Member]
Segment Reporting Information [Line Items]
Revenues									4,937,289	5,302,671	4,541,962
Operating income (loss)									362,328	462,985	523,355
Depreciation									89,150	76,214	64,913
Oil and Gas Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Revenues									2,635,147	2,444,558	1,869,615
Operating income (loss)									142,929	162,797	138,543
Depreciation									65,315	57,414	47,050
Corporate and Non-Allocated Costs [Member]
Segment Reporting Information [Line Items]
Operating income (loss)									(267,754)	(196,722)	(185,899)
Depreciation									$ 8,380	$ 7,478	$ 6,867

Quarterly Financial Data (Una87

Quarterly Financial Data (Unaudited) - Consolidated Operating Results by Quarter (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 1,899,272	$ 1,939,438	$ 1,872,340	$ 1,861,386	$ 2,027,614	$ 2,145,958	$ 1,838,209	$ 1,735,448	$ 7,572,436	$ 7,747,229	$ 6,411,577
Gross profit	223,039	235,215	227,505	237,906	311,628	336,903	264,209	256,054	923,665	1,168,794	986,933
Net income (loss)	(4,882)	218,956	49,565	58,185	70,975	100,015	85,444	58,648	321,824	315,082	421,309
Net income (loss) attributable to common stock	(5,074)	216,388	46,109	53,484	66,576	94,648	81,082	54,408	310,907	296,714	401,921
Net income (loss) from continuing operations attributable to common stock	$ (2,586)	$ 43,176	$ 32,007	$ 47,689	$ 60,406	$ 87,923	$ 73,453	$ 47,442	$ 120,286	$ 269,224	$ 372,057
Earnings (loss) per share from continuing operations attributable to common stock - basic and diluted	$ (0.02)	$ 0.23	$ 0.15	$ 0.22	$ 0.27	$ 0.40	$ 0.33	$ 0.22	$ 0.62	$ 1.22	$ 1.73

Quarterly Financial Data (Una88

Quarterly Financial Data (Unaudited) - Additional Information (Detail) - USD ($)	3 Months Ended					12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Data [Line Items]
Asset impairment charges	$ 58,500,000					$ 58,451,000
Asset impairment charges, net of tax	44,600,000
Goodwill impairment	39,800,000					39,826,000
Intangible asset impairment charges	12,100,000
Property and equipment impairment	$ 6,600,000						$ 0	$ 0
Provision for long-term contract receivable			$ 49,900,000	$ 52,500,000			102,460,000
Provision for long-term contract receivable, net of tax			$ 30,300,000	$ 32,300,000
Selling, general and administrative expenses						$ 592,863,000	$ 705,477,000	$ 485,069,000
Fiber Optic Licensing Division [Member]
Quarterly Financial Data [Line Items]
Gain on sale, Net of tax		$ 171,000,000
National Gas Company of Trinidad and Tobago Arbitration [Member]
Quarterly Financial Data [Line Items]
Selling, general and administrative expenses					$ 38,800,000
Selling, general and administrative expenses, Net of tax					$ 25,800,000