Quanta Services (PWR) 10-Q 6 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Nov. 05, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Trading Symbol	PWR
Entity Registrant Name	QUANTA SERVICES INC
Entity Central Index Key	1,050,915
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		152,882,049
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

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current Assets:
Cash and cash equivalents	$ 49,194	$ 190,515
Accounts receivable, net of allowances of $5,281 and $6,174	1,700,314	1,801,110
Costs and estimated earnings in excess of billings on uncompleted contracts	352,021	290,447
Inventories	64,690	38,921
Prepaid expenses and other current assets	196,445	210,267
Current assets of discontinued operations		22,716
Total current assets	2,362,664	2,553,976
Property and equipment, net of accumulated depreciation of $733,234 and $651,559	1,125,501	1,099,574
Other assets, net	62,915	79,133
Other intangible assets, net of accumulated amortization of $244,933 and $225,367	225,413	243,584
Goodwill	1,596,931	1,596,695
Non-current assets of discontinued operations		739,062
Total assets	5,373,424	6,312,024
Current Liabilities:
Current maturities of long-term debt and short-term borrowings	2,350	8,876
Accounts payable and accrued expenses	938,535	856,245
Billings in excess of costs and estimated earnings on uncompleted contracts	252,505	251,113
Current liabilities of discontinued operations	147,148	21,091
Total current liabilities	1,340,538	1,137,325
Long-term debt and notes payable, net of current maturities	348,209	72,489
Deferred income taxes	226,078	234,379
Insurance and other non-current liabilities	254,685	227,730
Non-current liabilities of discontinued operations		114,561
Total liabilities	$ 2,169,510	$ 1,786,484
Commitments and Contingencies
Equity:
Common stock, value	$ 2	$ 2
Additional paid-in capital	3,489,627	3,592,906
Retained earnings	1,682,772	1,366,791
Accumulated other comprehensive income (loss)	(264,844)	(123,290)
Treasury stock, 71,398,556 and 15,374,866 common shares, at cost	(1,718,185)	(321,936)
Total stockholders' equity	3,189,372	4,514,473
Non-controlling interests	14,542	11,067
Total equity	3,203,914	4,525,540
Total liabilities and equity	$ 5,373,424	$ 6,312,024
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

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Allowances on accounts receivable, current	$ 5,281	$ 6,174
Accumulated depreciation on property and equipment	733,234	651,559
Accumulated amortization on other intangible assets	$ 244,933	$ 225,367
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	227,855,948	226,194,656
Common stock, shares outstanding	156,457,392	210,819,790
Treasury stock, common shares	71,398,556	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

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Revenues	$ 1,939,438	$ 2,145,958	$ 5,673,164	$ 5,719,615
Cost of services (including depreciation)	1,704,223	1,809,055	4,972,538	4,862,449
Gross profit	235,215	336,903	700,626	857,166
Selling, general and administrative expenses	145,687	196,494	441,073	500,593
Amortization of intangible assets	8,650	9,125	25,674	25,160
Operating income	80,878	131,284	233,879	331,413
Interest expense	(2,021)	(1,321)	(5,096)	(3,431)
Interest income	346	900	1,118	3,041
Equity in earnings (losses) of unconsolidated affiliates			(314)	(332)
Other income (expense), net	(1,070)	(378)	(1,416)	(635)
Income from continuing operations before income taxes	78,133	130,485	228,171	330,056
Provision for income taxes	32,389	37,195	94,574	107,269
Net income from continuing operations	45,744	93,290	133,597	222,787
Net income from discontinued operations	173,212	6,725	193,109	21,320
Net income	218,956	100,015	326,706	244,107
Less: Net income attributable to non-controlling interests	2,568	5,367	10,725	13,969
Net income attributable to common stock	216,388	94,648	315,981	230,138
Amounts attributable to common stock:
Net income from continuing operations	43,176	87,923	122,872	208,818
Net income from discontinued operations	173,212	6,725	193,109	21,320
Net income attributable to common stock	$ 216,388	$ 94,648	$ 315,981	$ 230,138
Earnings per share attributable to common stock-basic and diluted:
Continuing operations	$ 0.23	$ 0.40	$ 0.59	$ 0.95
Discontinued operations	0.92	0.03	0.94	0.10
Net income attributable to common stock	$ 1.15	$ 0.43	$ 1.53	$ 1.05
Shares used in computing earnings per share:
Weighted average basic shares outstanding	188,951	219,492	206,181	219,395
Weighted average diluted shares outstanding	188,961	219,517	206,193	219,420

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 218,956	$ 100,015	$ 326,706	$ 244,107
Other comprehensive income (loss), net of tax provision:
Foreign currency translation adjustment, net of tax of $0, $0, $0 and $0	(67,497)	(50,053)	(141,549)	(36,656)
Other, net of tax of $3, $6, $1 and $18	(9)	(16)	(6)	(52)
Other comprehensive loss	(67,506)	(50,069)	(141,555)	(36,708)
Comprehensive income	151,450	49,946	185,151	207,399
Less: Comprehensive income attributable to non-controlling interests	2,568	5,367	10,725	13,969
Total comprehensive income attributable to Quanta stockholders	$ 148,882	$ 44,579	$ 174,426	$ 193,430

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustment, tax	$ 0	$ 0	$ 0	$ 0
Other comprehensive income other tax	$ 3	$ 6	$ 1	$ 18

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Cash Flows from Operating Activities of Continuing Operations:
Net income	$ 218,956	$ 100,015	$ 326,706	$ 244,107
Adjustments to reconcile net income to net cash provided by (used in) operating activities of continuing operations-
Income from discontinued operations	(173,212)	(6,725)	(193,109)	(21,320)
Depreciation	40,954	36,485	121,382	103,239
Amortization of intangible assets	8,650	9,125	25,674	25,160
Equity in losses of unconsolidated affiliates			314	332
Amortization of debt issuance costs	273	273	819	821
Gain on sale of property and equipment	(734)	(890)	(844)	(1,991)
Foreign currency loss	843	381	1,556	797
Provision for (recovery of) doubtful accounts	(645)	11	59	1,121
Provision for contract receivable		52,542		52,542
Non-cash portion of arbitration expense				10,518
Deferred income tax benefit	(7,544)	(13,215)	(6,552)	(13,760)
Non-cash stock-based compensation	9,523	7,397	28,708	27,249
Tax impact of stock-based equity awards	(665)	(1,185)	(669)	(1,429)
Changes in operating assets and liabilities, net of non-cash transactions - (Increase) decrease in -
Accounts and notes receivable	(59,739)	(216,792)	77,913	(374,751)
Costs and estimated earnings in excess of billings on uncompleted contracts	(11,828)	(96,008)	(78,597)	(100,844)
Inventories	(9,605)	1,058	(22,596)	(5,723)
Prepaid expenses and other current assets	14,305	(201)	4,729	(22,687)
Accounts payable and accrued expenses and other non-current liabilities	60,333	142,070	111,779	39,866
Billings in excess of costs and estimated earnings on uncompleted contracts	20,950	33,886	6,381	23,515
Other, net	(1,917)	2,121	(9,003)	6,199
Net cash provided by (used in) operating activities of continuing operations	108,898	50,348	394,650	(7,039)
Cash Flows from Investing Activities of Continuing Operations:
Proceeds from sale of property and equipment	8,471	2,941	17,486	9,482
Additions of property and equipment	(47,970)	(67,577)	(168,967)	(187,586)
Cash paid for acquisitions, net of cash acquired	(29,370)	(81,828)	(102,039)	(161,411)
Investments in equity from unconsolidated affiliates, net	(1,051)	176	(3,644)	(2,868)
Cash received from (paid for) other investments, net	(960)	(614)	2,233	1,656
Cash withdrawn from restricted cash			214
Cash paid for intangibles			(211)
Net cash used in investing activities of continuing operations	(70,880)	(146,902)	(254,928)	(340,727)
Cash Flows from Financing Activities of Continuing Operations:
Borrowings under credit facility	1,485,089	375,084	2,257,831	711,284
Payments under credit facility	(1,342,807)	(298,198)	(1,975,491)	(634,398)
Borrowings of other long-term debt		394		394
Payments on other long-term debt	(656)	(19,339)	(2,015)	(30,012)
Payments on short-term debt			(5,170)
Distributions to non-controlling interests	(1,500)	(3,000)	(6,503)	(3,506)
Tax impact of stock-based equity awards	665	1,185	669	1,429
Exercise of stock options		200	354	1,101
Repurchase of common stock, including accelerated stock repurchases	(1,175,293)		(1,529,572)	(45,021)
Net cash provided by (used in) financing activities of continuing operations	(1,034,502)	56,326	(1,259,897)	1,271
Discontinued operations:
Net cash provided by operating activities	1,311	14,952	22,342	44,562
Net cash provided by (used in) investing activities	980,880	(12,295)	959,699	(39,099)
Net cash provided by discontinued operations	982,191	2,657	982,041	5,463
Effect of foreign exchange rate changes on cash and cash equivalents	(1,940)	(7,218)	(3,187)	(3,586)
Net decrease in cash and cash equivalents	(16,233)	(44,789)	(141,321)	(344,618)
Cash and cash equivalents, beginning of period	65,427	188,948	190,515	488,777
Cash and cash equivalents, end of period	49,194	144,159	49,194	144,159
Supplemental disclosure of cash flow information:
Interest paid	(1,721)	(969)	(4,331)	(2,338)
Income taxes paid	(56,057)	(15,805)	(106,542)	(176,851)
Income tax refunds	$ 7,286	$ 5,363	$ 18,024	$ 6,655

Business and Organization

Business and Organization	9 Months Ended
	Sep. 30, 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. (Crown Castle) and CC SCN Fiber LLC, a subsidiary of Crown Castle, pursuant to which Quanta agreed to sell all of the issued and outstanding equity interests in Quanta Fiber Networks, Inc., a wholly owned subsidiary of Quanta that owned Quanta’s 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 unaudited condensed 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 the third quarter of 2015, Quanta acquired four companies, consisting of a foundation services company located in the United States, an electrical contracting company located in the United States, and an electrical engineering company located in Australia, all of the results of which are generally included in Quanta’s Electric Power Infrastructure Services segment, and a company that services above-ground storage tanks located in the United States, the results of which are generally included in Quanta’s Oil and Gas Infrastructure Services segment. During the second quarter of 2015, Quanta acquired three companies, consisting of a powerline construction company located in the United States, an engineering company located in Canada and an engineering, procurement and construction services company based in the United States, all the results of which are generally included in Quanta’s Electric Power Infrastructure Services segment. During the first quarter of 2015, Quanta acquired three companies, consisting of 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 results of which are generally included in Quanta’s Oil and Gas Infrastructure Services segment, and a supplier and material procurement specialist for the power and utility industry in Canada, the results of which are generally included in Quanta’s Electric Power Infrastructure Services segment. 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 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. Interim Condensed Consolidated Financial Information These unaudited condensed consolidated financial statements have been prepared pursuant to the rules of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures, normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (US GAAP), have been condensed or omitted pursuant to those rules and regulations. Quanta believes that the disclosures made are adequate to make the information presented not misleading. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary to fairly state the financial position, results of operations, comprehensive income and cash flows with respect to the interim condensed consolidated financial statements have been included. The results of operations and comprehensive income for the interim periods are not necessarily indicative of the results for the entire fiscal year. The results of Quanta have historically been subject to significant seasonal fluctuations. Quanta recommends that these unaudited condensed consolidated financial statements be read in conjunction with the audited consolidated financial statements and notes thereto of Quanta and its subsidiaries included in Quanta’s Annual Report on Form 10-K for the year ended December 31, 2014, which was filed with the SEC on March 2, 2015. 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, multi-employer 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 $49.2 million and $190.5 million as of September 30, 2015 and December 31, 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 September 30, 2015 and December 31, 2014, cash equivalents were $2.6 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 September 30, 2015 and December 31, 2014, Quanta had allowances for doubtful accounts on current receivables of approximately $5.3 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 September 30, 2015 and December 31, 2014 were approximately $298.2 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 September 30, 2015 and December 31, 2014 were $3.5 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 September 30, 2015 and December 31, 2014, the balances of unbilled receivables included in accounts receivable were approximately $255.3 million and $163.1 million. 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 Division and the Oil and Gas Infrastructure 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. 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 2014, 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. The analysis indicated that the implied fair value of each of Quanta’s reporting units, other than recently acquired reporting units, was substantially in excess of its carrying value. Following the analysis, management concluded that no impairment was indicated at any reporting unit. As discussed generally above, when evaluating the 2014 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 and, after giving consideration to at least a 10% decrease in the fair value of each of Quanta’s reporting units, the results of the assessment at December 31, 2014 did not change. However, circumstances such as market declines, unfavorable economic conditions, the loss of a major customer or other factors could impact the valuation 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. 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. 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 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 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. 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 nine months ended September 30, 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 September 30, 2015 and December 31, 2014, Quanta had approximately $132.1 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 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 September 30, 2015, the total amount of unrecognized tax benefits relating to uncertain tax positions was $53.3 million, an increase from December 31, 2014 of $2.4 million. This increase in unrecognized tax benefits resulted primarily from a $3.3 million increase due to tax positions expected to be taken for 2015, partially offset by a $0.9 million decrease due to audit settlements. Quanta is currently under examination by the Internal Revenue Service (IRS) for tax years 2011 and 2012 and remains open to examination by the IRS for tax years 2013 and 2014, as these statute of limitations periods have not yet expired. 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 $22.2 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 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 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 both the 2015-2016 and 2014-2015 policy years. 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 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 multi-employer pension plans and employee benefit trusts. Quanta’s multi-employer 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 multi-employer pension plan contribution obligation for future periods. 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

New Accounting Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 30, 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 will be 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. 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 revenue 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. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements. Quanta will adopt this guidance by 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. 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 for 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. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and will adopt this guidance by January 1, 2016.

Discontinued Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 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 of 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 unaudited condensed consolidated financial statements. The results were previously included in Quanta’s Fiber Optic Licensing and Other segment. Quanta will remain liable for all income 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 before tax related to Quanta’s fiber optic licensing operations (in thousands): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Major classes of line items constituting pretax income from fiber optic licensing operations: Revenues $ 8,736 $ 25,186 $ 59,998 $ 78,653 Expenses: Cost of services (including depreciation) 3,037 9,118 24,748 29,329 Selling, general and administrative expenses 366 4,027 10,247 12,699 Amortization of intangible assets 138 413 963 1,238 Other income (expense) items that are not major — 2 10 4 Net income before taxes of discontinued operations related to fiber optic licensing operations related to major classes of income before taxes 5,195 11,630 24,050 35,391 Pretax gain on the disposal of the discontinued operations 271,833 — 271,833 — Total pretax gain on discontinued operations 277,028 11,630 295,883 35,391 Provision for income taxes 103,816 4,905 102,774 14,071 Net income from discontinued operations related to fiber optic licensing operations as presented in the statements of operations $ 173,212 $ 6,725 $ 193,109 $ 21,320 The following represents a reconciliation of the carrying amounts of major classes of assets and liabilities of fiber optic licensing operations (in thousands): September 30, 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 — 11,287 Total current assets of fiber optic licensing operations $ — $ 22,716 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 $ 147,148 $ 21,091 Total current liabilities of fiber optic licensing operations $ 147,148 $ 21,091 Non-current liabilities: Deferred income taxes $ — $ 66,137 Long-term deferred revenue — 48,231 Total major classes of non-current liabilities of fiber optic licensing operations — 114,368 Other non-current liabilities of fiber optic licensing operations — 193 Total non-current liabilities of fiber optic licensing operations $ — $ 114,561

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
Acquisitions	5. ACQUISITIONS: 2015 Acquisitions During the first nine months of 2015, Quanta acquired ten companies. Seven of these acquired companies are generally included in Quanta’s Electric Power Infrastructure Services segment, including 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, and a supplier and material procurement specialist for the power and utility industry in Canada. The remaining three acquired companies are generally included in Quanta’s Oil and Gas Infrastructure Services segment, including 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 $98.9 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 an estimated $1.0 million in contingent consideration. As these transactions were effective during the first nine months of 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. 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 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 2015 and 2014 Acquisitions 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 September 30, 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. The aggregate purchase consideration related to the fourth quarter 2014 acquisitions was preliminarily allocated to acquired assets and assumed liabilities, which resulted in a preliminary allocation of approximately $71.1 million of net tangible assets, $56.3 million of goodwill and $45.1 million of other intangible assets. Additionally, the aggregate purchase consideration related to the 2015 acquisitions was preliminarily allocated to acquired assets and assumed liabilities, which resulted in a preliminary allocation of approximately $38.8 million of net tangible assets, $49.6 million of goodwill and $21.7 million of other intangible assets. The following table summarizes the aggregate consideration paid or payable through September 30, 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 98,941 279,533 Contingent consideration 1,001 — Fair value of total consideration transferred or estimated to be transferred $ 110,069 $ 414,071 Current assets $ 30,763 $ 172,121 Property and equipment 42,839 159,186 Other assets 4 3,501 Identifiable intangible assets 21,668 96,302 Current liabilities (22,317 ) (145,646 ) Deferred tax liabilities, net (7,583 ) (32,856 ) Other long-term liabilities (5,606 ) (4,926 ) Non-controlling interests 747 — Total identifiable net assets 60,515 247,682 Goodwill 49,554 166,389 $ 110,069 $ 414,071 The fair value of current assets acquired in 2015 included accounts receivable with a fair value of $17.9 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 and 2014 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 $27.2 million was recorded for the businesses acquired that were included within Quanta’s Electric Power Division and $22.4 million was recorded for the businesses acquired that were included within Quanta’s Oil and Gas Infrastructure 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 Division and $94.1 million was recorded for businesses included within Quanta’s Oil and Gas Infrastructure Division based on fair market values of assets and liabilities on the dates of acquisition. Goodwill of approximately $30.1 million is expected to be deductible for income tax purposes related to the businesses acquired in the first nine months of 2015, and goodwill of approximately $43.5 million is expected to be deductible for income tax purposes related to the businesses acquired in 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 $ 13,856 13.5 Backlog 2,118 1.1 Trade names 3,752 8.4 Non-compete agreements 1,942 5.0 Total intangible assets subject to amortization acquired in 2015 acquisitions $ 21,668 10.6 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): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Revenues $ 1,943,906 $ 2,316,002 $ 5,722,741 $ 6,313,290 Gross profit $ 236,364 $ 353,021 $ 713,434 $ 920,610 Selling, general and administrative expenses $ 146,224 $ 203,797 $ 447,462 $ 533,555 Amortization of intangible assets $ 8,694 $ 11,868 $ 26,230 $ 34,745 Net income from continuing operations $ 46,032 $ 96,598 $ 137,039 $ 235,320 Net income from continuing operations attributable to common stock $ 43,464 $ 91,231 $ 126,314 $ 221,351 Earnings per share from continuing operations attributable to common stock — basic and diluted $ 0.23 $ 0.41 $ 0.61 $ 0.99 The pro forma combined results of operations for the three and nine months ended September 30, 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 three and nine months ended September 30, 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. 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 and 2014 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 and 2014 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 $36.5 million and income before taxes of approximately $0.6 million, which included $1.9 million of acquisition costs, were included in Quanta’s consolidated results of operations for the three months ended September 30, 2015 related to the 2015 acquisitions following their respective dates of acquisition. Revenues of approximately $61.6 million and a loss before income taxes of approximately $0.6 million, which included $3.6 million of acquisition costs, were included in Quanta’s consolidated results of operations for the nine months ended September 30, 2015 related to the 2015 acquisitions following their respective dates of acquisition.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 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 Division Oil and Gas Division Total Goodwill balance at December 31, 2014 $ 1,223,224 $ 373,471 $ 1,596,695 Goodwill acquired during 2015 27,197 22,357 49,554 Purchase price allocation adjustments 750 (8,863 ) (8,113 ) Foreign currency translation adjustments (23,811 ) (17,394 ) (41,205 ) Goodwill balance at September 30, 2015 $ 1,227,360 $ 369,571 $ 1,596,931 As described in Note 2, Quanta’s operating units are organized into one of Quanta’s two internal divisions and, accordingly, Quanta’s goodwill associated with each of 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 based on the predominant type of work performed by the operating units within the divisions. From time to time, operating units may be reorganized among Quanta’s internal divisions, as Quanta periodically re-evaluates strategies to better align its operations 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 As of As of September 30, 2015 December 31, 2014 September 30, 2015 Intangible Assets Accumulated Amortization Intangible Assets, Net Intangible Assets Accumulated Amortization Intangible Assets, Net Remaining Average Customer relationships $ 236,677 $ (75,235 ) $ 161,442 $ 235,851 $ (63,764 ) $ 172,087 9.9 Backlog 131,312 (125,410 ) 5,902 133,704 (122,265 ) 11,439 0.9 Trade names 51,298 (8,340 ) 42,958 49,664 (6,278 ) 43,386 18.8 Non-compete agreements 28,583 (22,633 ) 5,950 27,659 (21,365 ) 6,294 3.5 Patented rights and developed technology 22,476 (13,315 ) 9,161 22,073 (11,695 ) 10,378 4.2 Total intangible assets subject to amortization $ 470,346 $ (244,933 ) $ 225,413 $ 468,951 $ (225,367 ) $ 243,584 11.0 Amortization expense for intangible assets was $8.7 million and $9.1 million for the three months ended September 30, 2015 and 2014 and $25.7 million and $25.2 million for the nine months ended September 30, 2015 and 2014. The estimated future aggregate amortization expense of intangible assets subject to amortization as of September 30, 2015 is set forth below (in thousands): For the Fiscal Year Ending December 31, Remainder of 2015 $ 8,891 2016 29,365 2017 23,965 2018 23,273 2019 22,351 Thereafter 117,568 Total $ 225,413

Per Share Information

Per Share Information	9 Months Ended
	Sep. 30, 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 three and nine months ended September 30, 2015 and 2014 are illustrated below (in thousands): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Amounts attributable to common stock: Net income from continuing operations $ 43,176 $ 87,923 $ 122,872 $ 208,818 Net income from discontinued operations 173,212 6,725 193,109 21,320 Net income attributable to common stock $ 216,388 $ 94,648 $ 315,981 $ 230,138 Weighted average shares: Weighted average shares outstanding for basic earnings per share 188,951 219,492 206,181 219,395 Effect of dilutive stock options 10 25 12 25 Weighted average shares outstanding for diluted earnings per share 188,961 219,517 206,193 219,420 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 9), 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 three and nine months ended September 30, 2015 and 2014 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 (as further described in Note 9) have not been included in the weighted average shares outstanding for basic and diluted earnings per share for the three and nine months ended September 30, 2015 because their effect would be anti-dilutive.

Debt Obligations

Debt Obligations	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Debt Obligations	8. DEBT OBLIGATIONS: Quanta’s long-term debt obligations consisted of the following (in thousands): September 30, December 31, Borrowings under credit facility $ 339,159 $ 68,793 Other long-term debt, interest rates ranging from 1.4% to 4.3% 5,624 6,370 Capital leases, interest rates ranging from 6.0% to 7.3% 5,776 1,146 Total long-term debt obligations 350,559 76,309 Less — Current maturities of long-term debt 2,350 3,820 Total long-term debt obligations, net of current maturities $ 348,209 $ 72,489 Quanta’s current maturities of long-term debt and short-term borrowings consisted of the following (in thousands): September 30, December 31, Short-term borrowings $ — $ 5,056 Current maturities of long-term debt 2,350 3,820 Current maturities of long-term debt and short-term borrowings $ 2,350 $ 8,876 Credit Facility On October 30, 2013, Quanta entered into an amended and restated credit agreement with various lenders that provides for a $1.325 billion senior secured revolving credit facility maturing October 30, 2018. The entire amount available may be used for revolving loans and letters of credit in U.S. dollars and certain foreign currencies. Swing line loans are limited to $50.0 million in U.S. dollars, $30.0 million in Canadian dollars and $20.0 million 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 $300.0 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 September 30, 2015, Quanta had approximately $318.5 million of outstanding letters of credit and bank guarantees, $226.1 million of which was denominated in U.S. dollars and $92.4 million of which was denominated in Australian or Canadian dollars. Quanta also had $339.2 million of outstanding borrowings under the credit facility, $97.7 million of which was denominated in Canadian dollars and $241.5 million of which was denominated in U.S. dollars. The remaining $667.3 million was available for borrowings or issuing new letters of credit or bank guarantees. Information on borrowings under Quanta’s credit facility and the applicable interest rates during the three and nine months ended September 30, 2015 and 2014 is as follows (dollars in thousands): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Maximum amount outstanding during the period $ 470,560 $ 130,856 $ 470,560 $ 130,856 Average daily amount outstanding under the credit facility $ 285,051 $ 35,129 $ 183,719 $ 19,743 Weighted-average interest rate 1.77 % 2.75 % 2.01 % 2.71 % Effective April 1, 2014, amounts borrowed under the credit agreement 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. Prior to April 1, 2014, amounts borrowed under the credit agreement 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%. Amounts borrowed as revolving loans under the credit agreement in any currency other than U.S. dollars bore interest at a rate equal to the Eurocurrency Rate plus 1.25%. Standby letters of credit issued under the credit agreement were subject to a letter of credit fee of 1.25%, and Performance Letters of Credit issued under the credit agreement in support of certain contractual obligations were subject to a letter of credit fee of 0.75%. Quanta was also subject to a commitment fee of 0.20% 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 million of availability under the credit agreement and/or cash and cash equivalents on hand. As of September 30, 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 other debt instruments exceeding $75.0 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.

Equity

Equity	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Equity	9. 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 the quarter ended September 30, 2015, 449,929 exchangeable shares associated with the Preferred Stock were exchanged for Quanta common stock. As of September 30, 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 10, 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 0.4 million and 0.3 million shares of Quanta common stock during the nine months ended September 30, 2015 and 2014, with a total market value of $10.1 million and $11.9 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 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 third quarter of 2015, Quanta completed the 2013 Repurchase Program by purchasing 1.8 million shares of its common stock at a cost of $52.2 million. During the third quarter of 2015, Quanta’s board of directors also 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 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 have been accounted for as an adjustment to the balance of treasury stock as of September 30, 2015, reducing the weighted-average number of basic and diluted common shares used to calculate Quanta’s earnings per share. The $150.0 million remaining under the ASR was recorded as an adjustment to additional paid-in capital (APIC) as of 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 quarter of 2015, Quanta repurchased 15.6 million shares of its common stock at a cost of $373.1 million in the open market under the 2015 Repurchase Program. During the three and nine months ended September 30, 2015, Quanta repurchased a total of 43.1 million and 55.7 million shares valued at $1.03 billion and $1.38 billion pursuant to both the 2013 Repurchase Program and the 2015 Repurchase Program. The shares and the related cost to acquire them have been accounted for as an adjustment to the balance of treasury stock. During the fourth quarter of 2015, Quanta repurchased an additional 3.6 million shares of its common stock at a cost of $76.8 million in the open market under its 2015 Repurchase Program. 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 condensed consolidated financial statements. Income attributable to the other joint venture members in the amounts of $2.6 million and $5.4 million for the three months ended September 30, 2015 and 2014 and $10.7 million and $14.0 million for the nine months ended September 30, 2015 or 2014 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 $14.5 million and $11.1 million at September 30, 2015 and December 31, 2014. The carrying value of investments held by the non-controlling interests in these variable interest entities at September 30, 2015 and December 31, 2014 was $14.5 million and $11.1 million. During the three months ended September 30, 2015 and 2014, distributions to non-controlling interests were $1.5 million and $3.0 million. During the nine months ended September 30, 2015 and 2014, distributions to non-controlling interests were $6.5 million and $3.5 million. There were no other changes in equity as a result of transfers to/from the non-controlling interests during the nine months ended September 30, 2015 or 2014. See Note 11 for further disclosures related to Quanta’s joint venture arrangements.

Equity-Based Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity-Based Compensation	10. 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. Restricted Stock and RSUs to be Settled in Common Stock During the three months ended September 30, 2015 and 2014, Quanta granted 0.1 million and a nominal amount of RSUs to be settled in common stock under the Plans with weighted average grant date fair values of $24.58 and $36.28. During the nine months ended September 30, 2015 and 2014, Quanta granted 1.3 million and 1.4 million RSUs to be settled in common stock under the Plans with weighted average grant date fair values of $27.70 and $35.13. 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 on such shares. During the three months ended September 30, 2015 and 2014, vesting activity consisted of 0.1 million and a nominal amount of shares of restricted stock and RSUs settled in common stock with an approximate fair value at the time of vesting of $1.2 million and $1.2 million. During the nine months ended September 30, 2015 and 2014, vesting activity consisted of 1.2 million and 1.0 million shares of restricted stock and RSUs settled in common stock with an approximate fair value at the time of vesting of $35.0 million and $36.0 million. As of September 30, 2015, there was approximately $38.7 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 1.68 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 three months ended September 30, 2015 and 2014, Quanta granted no performance units to be settled in common stock under the 2011 Plan. During the nine months ended September 30, 2015, Quanta granted 0.2 million performance units to be settled in common stock under the 2011 Plan, with a weighted average grant date fair value of $28.16 per share. 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 three and nine months ended September 30, 2015, Quanta recognized $1.1 million and $2.6 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 three and nine months ended September 30, 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, Quanta’s non-employee directors may elect to settle a portion of their RSU awards in cash as long as they meet certain stock ownership requirements. This cash settlement option is intended to provide non-employee directors with the cash necessary to cover taxes due at settlement of their RSU awards. RSU awards for non-employee directors vest shortly after the conclusion of each director service year; however, settlement may be deferred based on prior elections under a nonqualified deferred compensation plan maintained by Quanta. 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 $0.7 million and $1.6 million for the three months ended September 30, 2015 and 2014 and $3.2 million for both the nine months ended September 30, 2015 and 2014. 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 $1.2 million and $0.7 million to settle liabilities related to cash-settled RSUs in the three months ended September 30, 2015 and 2014 and $3.7 million and $2.9 million to settle liabilities related to cash-settled RSUs in the nine months ended September 30, 2015 and 2014. Accrued liabilities for the estimated earned value of outstanding RSUs to be settled in cash were $2.4 million and $2.9 million at September 30, 2015 and December 31, 2014.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	11. COMMITMENTS AND CONTINGENCIES: Investments in Affiliates and Other Entities As described in Note 9, 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 September 30, 2015, Quanta had outstanding capital commitments associated with investments in an unconsolidated affiliate related to this project as follows (in thousands): Capital Year Ending December 31 — Remainder of 2015 $ 2,530 2016 8,010 2017 (1) 32,238 2018 — 2019 23,801 Thereafter — Total capital commitments associated with investments in unconsolidated affiliated related to an EPC electrical transmission project $ 66,579 (1) This amount excludes a return of capital from an unconsolidated affiliate of approximately $42.5 million that is anticipated in August 2017. Additionally, as of September 30, 2015, Quanta had outstanding capital commitments associated with investments in unconsolidated affiliates related to planned midstream infrastructure projects of approximately $8.5 million, $1.2 million of which is expected to be paid in the fourth quarter of 2015. Quanta is unable to determine the exact timing of the remaining $7.3 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. 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 September 30, 2015 (in thousands): Operating Year Ending December 31 — Remainder of 2015 $ 23,170 2016 68,570 2017 51,415 2018 38,039 2019 21,750 Thereafter 29,735 Total minimum lease payments $ 232,679 Rent expense related to operating leases was approximately $52.3 million and $38.0 million for the three months ended September 30, 2015 and 2014 and approximately $152.5 million and $115.2 million for the nine months ended September 30, 2015 and 2014. 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 September 30, 2015, the maximum guaranteed residual value was approximately $480.7 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 September 30, 2015, Quanta issued approximately $5.3 million of production orders with expected delivery dates in 2015 and approximately $0.5 million of production orders with 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. No customers represented 10% or more of Quanta’s revenues for the three and nine months ended September 30, 2015 and 2014, and no customers represented 10% or more of Quanta’s consolidated net position as of September 30, 2015 or December 31, 2014. Self-Insurance As discussed in Note 2, Quanta is insured for employer’s liability, general liability, auto liability and workers’ compensation claims. As of September 30, 2015 and December 31, 2014, the gross amount accrued for insurance claims totaled $194.6 million and $170.2 million with $150.6 million and $130.8 million considered to be long-term and included in other non-current liabilities. Related insurance recoveries/receivables as of September 30, 2015 and December 31, 2014 were $8.7 million and $9.1 million, of which $0.5 million and $0.8 million were included in prepaid expenses and other current assets and $8.2 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 September 30, 2015, Quanta had $318.5 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 2015 and 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 September 30, 2015, the total amount of outstanding performance bonds was estimated to be approximately $2.4 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 $786 million as of September 30, 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 multi-employer pension plans and employee benefit trusts. Quanta’s multi-employer 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 multi-employer pension plan contribution obligation for future periods. The Pension Protection Act of 2006 (PPA) also added special funding and operational rules generally applicable to plan years beginning after 2007 for multi-employer 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 multi-employer defined benefit pension plans. For example, the Employee Retirement Income Security Act of 1974, as amended by the Multi-Employer Pension Plan Amendments Act of 1980, imposes certain liabilities upon an employer who is a contributor to a multi-employer 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 multi-employer 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. The partial withdrawal liability amount was 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. The District Court ruled in September 2013 that the withdrawal of the PLCA members was not effective in 2011, and that decision was appealed by the PLCA. In September 2015, the United States Court of Appeals for the Seventh Circuit ruled in favor of the PLCA. While this outcome is a positive result for the PLCA, the full effect of the ruling on the ultimate liability stake for Quanta is still under evaluation. 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. 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. In July 2014, the Central States Plan also provided Quanta with a Notice and Demand of partial withdrawal liability for certain Quanta entities in the amount of $39.6 million. Quanta continues to dispute the total withdrawal liability owed to the Central States Plan; however, Quanta began to make monthly payments associated with this Notice and Demand in the third quarter of 2014 while the parties continue the related process to determine the final withdrawal liability. The amount owed upon resolution of this matter will be reduced by the total amount of monthly payments made. 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. 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 will seek to challenge and further negotiate the amount owed in connection with this matter. However, 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 the Central States Plan is up to $55.4 million. 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 liability Quanta has recognized through September 30, 2015. Central States Plan Grievance Matter 2013 Central States Plan Withdrawal Liability. 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 September 30, 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, as the indemnities under acquisition agreements are usually contingent upon Quanta incurring liabilities that reach specified thresholds, and the indemnitors may be unwilling or unable to pay the amounts owed to Quanta. 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 September 30, 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	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment Information	12. 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 Division and the Oil and Gas Infrastructure 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): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Revenues: Electric Power Infrastructure $ 1,183,151 $ 1,396,157 $ 3,645,767 $ 3,938,590 Oil and Gas Infrastructure 756,287 749,801 2,027,397 1,781,025 Consolidated $ 1,939,438 $ 2,145,958 $ 5,673,164 $ 5,719,615 Operating income (loss) Electric Power Infrastructure $ 76,948 $ 104,365 $ 273,967 $ 361,689 Oil and Gas Infrastructure 58,874 74,824 119,002 109,235 Corporate and non-allocated costs (54,944 ) (47,905 ) (159,090 ) (139,511 ) Consolidated $ 80,878 $ 131,284 $ 233,879 $ 331,413 Depreciation: Electric Power Infrastructure $ 22,801 $ 19,406 $ 65,790 $ 55,896 Oil and Gas Infrastructure 16,347 15,146 49,599 41,826 Corporate and non-allocated costs 1,806 1,933 5,993 5,517 Consolidated $ 40,954 $ 36,485 $ 121,382 $ 103,239 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 the three months ended September 30, 2015 and 2014, Quanta derived $342.6 million and $523.7 million of its revenues from foreign operations. During the nine months ended September 30, 2015 and 2014, Quanta derived $1.24 billion and $1.37 billion of its revenues from foreign operations. The decreases in foreign revenues for the three and nine months ended September 30, 2015 were primarily attributable to reduced customer spending arising from regulatory and permitting delays on certain projects, normal fluctuations in project timing, and the decline in oil prices. Also contributing to the decreases were less favorable currency exchange rates. Of Quanta’s foreign revenues, approximately 83% was earned in Canada during both the three months ended September 30, 2015 and 2014, and approximately 85% and 81% was earned in Canada in the nine months ended September 30, 2015 and 2014. In addition, Quanta held property and equipment of $337.2 million and $372.9 million in foreign countries, primarily Canada, as of September 30, 2015 and December 31, 2014.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	13. SUBSEQUENT EVENTS: Acquisitions During the fourth quarter of 2015, Quanta has completed one acquisition. The company acquired is an underground construction contracting company located in Canada, the results of which will generally be included in Quanta’s Electric Power Infrastructure Services segment. The aggregate consideration paid or payable for this acquisition was approximately $9.6 million in cash, subject to certain adjustments. As this transaction was effective during the fourth quarter of 2015, the results will be included in Quanta’s consolidated financial statements beginning on the date of acquisition. This acquisition should enable Quanta to further enhance its electric power infrastructure service offerings in Canada.

Summary of Significant Accoun21

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 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.
Interim Condensed Consolidated Financial Information	Interim Condensed Consolidated Financial Information These unaudited condensed consolidated financial statements have been prepared pursuant to the rules of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures, normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (US GAAP), have been condensed or omitted pursuant to those rules and regulations. Quanta believes that the disclosures made are adequate to make the information presented not misleading. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary to fairly state the financial position, results of operations, comprehensive income and cash flows with respect to the interim condensed consolidated financial statements have been included. The results of operations and comprehensive income for the interim periods are not necessarily indicative of the results for the entire fiscal year. The results of Quanta have historically been subject to significant seasonal fluctuations. Quanta recommends that these unaudited condensed consolidated financial statements be read in conjunction with the audited consolidated financial statements and notes thereto of Quanta and its subsidiaries included in Quanta’s Annual Report on Form 10-K for the year ended December 31, 2014, which was filed with the SEC on March 2, 2015.
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, multi-employer 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 $49.2 million and $190.5 million as of September 30, 2015 and December 31, 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 September 30, 2015 and December 31, 2014, cash equivalents were $2.6 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 September 30, 2015 and December 31, 2014, Quanta had allowances for doubtful accounts on current receivables of approximately $5.3 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 September 30, 2015 and December 31, 2014 were approximately $298.2 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 September 30, 2015 and December 31, 2014 were $3.5 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 September 30, 2015 and December 31, 2014, the balances of unbilled receivables included in accounts receivable were approximately $255.3 million and $163.1 million.
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 Division and the Oil and Gas Infrastructure 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. 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 2014, 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. The analysis indicated that the implied fair value of each of Quanta’s reporting units, other than recently acquired reporting units, was substantially in excess of its carrying value. Following the analysis, management concluded that no impairment was indicated at any reporting unit. As discussed generally above, when evaluating the 2014 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 and, after giving consideration to at least a 10% decrease in the fair value of each of Quanta’s reporting units, the results of the assessment at December 31, 2014 did not change. However, circumstances such as market declines, unfavorable economic conditions, the loss of a major customer or other factors could impact the valuation 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. 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.
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 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 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.
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 nine months ended September 30, 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 September 30, 2015 and December 31, 2014, Quanta had approximately $132.1 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 September 30, 2015, the total amount of unrecognized tax benefits relating to uncertain tax positions was $53.3 million, an increase from December 31, 2014 of $2.4 million. This increase in unrecognized tax benefits resulted primarily from a $3.3 million increase due to tax positions expected to be taken for 2015, partially offset by a $0.9 million decrease due to audit settlements. Quanta is currently under examination by the Internal Revenue Service (IRS) for tax years 2011 and 2012 and remains open to examination by the IRS for tax years 2013 and 2014, as these statute of limitations periods have not yet expired. 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 $22.2 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 both the 2015-2016 and 2014-2015 policy years. 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 multi-employer pension plans and employee benefit trusts. Quanta’s multi-employer 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 multi-employer 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 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, RSU and performance unit awards, see Note 10.
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, which involves consideration of all relevant economic facts and circumstances affecting the 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. This 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.
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 11.
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 September 30, 2015 and December 31, 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, 2014, 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 will be 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.
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 revenue 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. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements. Quanta will adopt this guidance by 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. 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 for 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. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and will adopt this guidance by January 1, 2016.
Repurchase of Common Stock	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 third quarter of 2015, Quanta completed the 2013 Repurchase Program by purchasing 1.8 million shares of its common stock at a cost of $52.2 million. During the third quarter of 2015, Quanta’s board of directors also 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 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 have been accounted for as an adjustment to the balance of treasury stock as of September 30, 2015, reducing the weighted-average number of basic and diluted common shares used to calculate Quanta’s earnings per share. The $150.0 million remaining under the ASR was recorded as an adjustment to additional paid-in capital (APIC) as of 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 quarter of 2015, Quanta repurchased 15.6 million shares of its common stock at a cost of $373.1 million in the open market under the 2015 Repurchase Program. During the three and nine months ended September 30, 2015, Quanta repurchased a total of 43.1 million and 55.7 million shares valued at $1.03 billion and $1.38 billion pursuant to both the 2013 Repurchase Program and the 2015 Repurchase Program. The shares and the related cost to acquire them have been accounted for as an adjustment to the balance of treasury stock. During the fourth quarter of 2015, Quanta repurchased an additional 3.6 million shares of its common stock at a cost of $76.8 million in the open market under its 2015 Repurchase Program.
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 Division and the Oil and Gas Infrastructure 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. 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.

Discontinued Operations (Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2015
Discontinued Operations and Disposal Groups [Abstract]
Summary of Financial Information for Fiber Optic Licensing Operations	The following represents a reconciliation of the major classes of line items constituting income from discontinued operations before tax related to Quanta’s fiber optic licensing operations (in thousands): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Major classes of line items constituting pretax income from fiber optic licensing operations: Revenues $ 8,736 $ 25,186 $ 59,998 $ 78,653 Expenses: Cost of services (including depreciation) 3,037 9,118 24,748 29,329 Selling, general and administrative expenses 366 4,027 10,247 12,699 Amortization of intangible assets 138 413 963 1,238 Other income (expense) items that are not major — 2 10 4 Net income before taxes of discontinued operations related to fiber optic licensing operations related to major classes of income before taxes 5,195 11,630 24,050 35,391 Pretax gain on the disposal of the discontinued operations 271,833 — 271,833 — Total pretax gain on discontinued operations 277,028 11,630 295,883 35,391 Provision for income taxes 103,816 4,905 102,774 14,071 Net income from discontinued operations related to fiber optic licensing operations as presented in the statements of operations $ 173,212 $ 6,725 $ 193,109 $ 21,320 The following represents a reconciliation of the carrying amounts of major classes of assets and liabilities of fiber optic licensing operations (in thousands): September 30, 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 — 11,287 Total current assets of fiber optic licensing operations $ — $ 22,716 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 $ 147,148 $ 21,091 Total current liabilities of fiber optic licensing operations $ 147,148 $ 21,091 Non-current liabilities: Deferred income taxes $ — $ 66,137 Long-term deferred revenue — 48,231 Total major classes of non-current liabilities of fiber optic licensing operations — 114,368 Other non-current liabilities of fiber optic licensing operations — 193 Total non-current liabilities of fiber optic licensing operations $ — $ 114,561

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 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 98,941 279,533 Contingent consideration 1,001 — Fair value of total consideration transferred or estimated to be transferred $ 110,069 $ 414,071 Current assets $ 30,763 $ 172,121 Property and equipment 42,839 159,186 Other assets 4 3,501 Identifiable intangible assets 21,668 96,302 Current liabilities (22,317 ) (145,646 ) Deferred tax liabilities, net (7,583 ) (32,856 ) Other long-term liabilities (5,606 ) (4,926 ) Non-controlling interests 747 — Total identifiable net assets 60,515 247,682 Goodwill 49,554 166,389 $ 110,069 $ 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 $ 13,856 13.5 Backlog 2,118 1.1 Trade names 3,752 8.4 Non-compete agreements 1,942 5.0 Total intangible assets subject to amortization acquired in 2015 acquisitions $ 21,668 10.6
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): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Revenues $ 1,943,906 $ 2,316,002 $ 5,722,741 $ 6,313,290 Gross profit $ 236,364 $ 353,021 $ 713,434 $ 920,610 Selling, general and administrative expenses $ 146,224 $ 203,797 $ 447,462 $ 533,555 Amortization of intangible assets $ 8,694 $ 11,868 $ 26,230 $ 34,745 Net income from continuing operations $ 46,032 $ 96,598 $ 137,039 $ 235,320 Net income from continuing operations attributable to common stock $ 43,464 $ 91,231 $ 126,314 $ 221,351 Earnings per share from continuing operations attributable to common stock — basic and diluted $ 0.23 $ 0.41 $ 0.61 $ 0.99

Goodwill and Other Intangible24

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 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 Division Oil and Gas Division Total Goodwill balance at December 31, 2014 $ 1,223,224 $ 373,471 $ 1,596,695 Goodwill acquired during 2015 27,197 22,357 49,554 Purchase price allocation adjustments 750 (8,863 ) (8,113 ) Foreign currency translation adjustments (23,811 ) (17,394 ) (41,205 ) Goodwill balance at September 30, 2015 $ 1,227,360 $ 369,571 $ 1,596,931
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 As of As of September 30, 2015 December 31, 2014 September 30, 2015 Intangible Assets Accumulated Amortization Intangible Assets, Net Intangible Assets Accumulated Amortization Intangible Assets, Net Remaining Average Customer relationships $ 236,677 $ (75,235 ) $ 161,442 $ 235,851 $ (63,764 ) $ 172,087 9.9 Backlog 131,312 (125,410 ) 5,902 133,704 (122,265 ) 11,439 0.9 Trade names 51,298 (8,340 ) 42,958 49,664 (6,278 ) 43,386 18.8 Non-compete agreements 28,583 (22,633 ) 5,950 27,659 (21,365 ) 6,294 3.5 Patented rights and developed technology 22,476 (13,315 ) 9,161 22,073 (11,695 ) 10,378 4.2 Total intangible assets subject to amortization $ 470,346 $ (244,933 ) $ 225,413 $ 468,951 $ (225,367 ) $ 243,584 11.0
Estimated Future Aggregate Amortization Expense of Intangible Assets	The estimated future aggregate amortization expense of intangible assets subject to amortization as of September 30, 2015 is set forth below (in thousands): For the Fiscal Year Ending December 31, Remainder of 2015 $ 8,891 2016 29,365 2017 23,965 2018 23,273 2019 22,351 Thereafter 117,568 Total $ 225,413

Per Share Information (Tables)

Per Share Information (Tables)	9 Months Ended
	Sep. 30, 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 three and nine months ended September 30, 2015 and 2014 are illustrated below (in thousands): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Amounts attributable to common stock: Net income from continuing operations $ 43,176 $ 87,923 $ 122,872 $ 208,818 Net income from discontinued operations 173,212 6,725 193,109 21,320 Net income attributable to common stock $ 216,388 $ 94,648 $ 315,981 $ 230,138 Weighted average shares: Weighted average shares outstanding for basic earnings per share 188,951 219,492 206,181 219,395 Effect of dilutive stock options 10 25 12 25 Weighted average shares outstanding for diluted earnings per share 188,961 219,517 206,193 219,420

Debt Obligations (Tables)

Debt Obligations (Tables)	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Long-term Debt Obligations	Quanta’s long-term debt obligations consisted of the following (in thousands): September 30, 2015 December 31, 2014 Borrowings under credit facility $ 339,159 $ 68,793 Other long-term debt, interest rates ranging from 1.4% to 4.3% 5,624 6,370 Capital leases, interest rates ranging from 6.0% to 7.3% 5,776 1,146 Total long-term debt obligations 350,559 76,309 Less — Current maturities of long-term debt 2,350 3,820 Total long-term debt obligations, net of current maturities $ 348,209 $ 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): September 30, 2015 December 31, 2014 Short-term borrowings $ — $ 5,056 Current maturities of long-term debt 2,350 3,820 Current maturities of long-term debt and short-term borrowings $ 2,350 $ 8,876
Information on Borrowings under Current and Prior Credit Facility and Applicable Interest Rates	Information on borrowings under Quanta’s credit facility and the applicable interest rates during the three and nine months ended September 30, 2015 and 2014 is as follows (dollars in thousands): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Maximum amount outstanding during the period $ 470,560 $ 130,856 $ 470,560 $ 130,856 Average daily amount outstanding under the credit facility $ 285,051 $ 35,129 $ 183,719 $ 19,743 Weighted-average interest rate 1.77 % 2.75 % 2.01 % 2.71 %

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Outstanding Capital Commitments Associated with Investments in Unconsolidated Affiliates	As of September 30, 2015, Quanta had outstanding capital commitments associated with investments in an unconsolidated affiliate related to this project as follows (in thousands): Capital Year Ending December 31 — Remainder of 2015 $ 2,530 2016 8,010 2017 (1) 32,238 2018 — 2019 23,801 Thereafter — Total capital commitments associated with investments in unconsolidated affiliated related to an EPC electrical transmission project $ 66,579 (1) This amount excludes a return of capital from an unconsolidated affiliate of approximately $42.5 million that is anticipated in August 2017.
Minimum Lease Payments	The following schedule shows the future minimum lease payments under these leases as of September 30, 2015 (in thousands): Operating Year Ending December 31 — Remainder of 2015 $ 23,170 2016 68,570 2017 51,415 2018 38,039 2019 21,750 Thereafter 29,735 Total minimum lease payments $ 232,679

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Summarized Financial Information	Summarized financial information for Quanta’s reportable segments is presented in the following table (in thousands): Three Months Ended Nine Months Ended 2015 2014 2015 2014 Revenues: Electric Power Infrastructure $ 1,183,151 $ 1,396,157 $ 3,645,767 $ 3,938,590 Oil and Gas Infrastructure 756,287 749,801 2,027,397 1,781,025 Consolidated $ 1,939,438 $ 2,145,958 $ 5,673,164 $ 5,719,615 Operating income (loss) Electric Power Infrastructure $ 76,948 $ 104,365 $ 273,967 $ 361,689 Oil and Gas Infrastructure 58,874 74,824 119,002 109,235 Corporate and non-allocated costs (54,944 ) (47,905 ) (159,090 ) (139,511 ) Consolidated $ 80,878 $ 131,284 $ 233,879 $ 331,413 Depreciation: Electric Power Infrastructure $ 22,801 $ 19,406 $ 65,790 $ 55,896 Oil and Gas Infrastructure 16,347 15,146 49,599 41,826 Corporate and non-allocated costs 1,806 1,933 5,993 5,517 Consolidated $ 40,954 $ 36,485 $ 121,382 $ 103,239

Business and Organization - Add

Business and Organization - Additional Information (Detail) $ in Millions	Aug. 04, 2015USD ($)	Sep. 30, 2015USD ($)Entity	Jun. 30, 2015Entity	Mar. 31, 2015Entity	Sep. 30, 2015EntitySegment	Dec. 31, 2014Entity
Organization And Description Of Business [Line Items]
Number of reportable segments | Segment					2
Number of business acquisitions		4	3	3	10	9
Electric Power Infrastructure Services Business [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions					7
Electric Power Infrastructure Services Business [Member] | Canada [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions			1	1	2	4
Electric Power Infrastructure Services Business [Member] | Australia [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions		1			1	1
Electric Power Infrastructure Services Business [Member] | United States [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions		2	2		4	1
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	1	2
Oil and Gas Infrastructure Services Business [Member] | Australia [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions				1	1
Oil and Gas Infrastructure Services Business [Member] | United States [Member]
Organization And Description Of Business [Line Items]
Number of business acquisitions		1			1	1
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 Accoun30

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 49,194,000	$ 144,159,000	$ 190,515,000	$ 65,427,000	$ 188,948,000	$ 488,777,000
Cash equivalents	$ 2,600,000		$ 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	$ 5,281,000		$ 6,174,000
Current retainage balances	298,200,000		307,300,000
Non-current retainage balances	3,500,000		19,600,000
Unbilled receivables	255,300,000		$ 163,100,000
Decrease in fair value of reporting units considered for impairment calculation			10.00%
Change orders and/or claims	132,100,000		$ 106,800,000
Total amount of unrecognized tax benefits relating to uncertain tax positions	53,300,000
Amount of unrecognized tax benefits change from year end relating to uncertain tax positions	2,400,000
Unrecognized tax benefits increase resulting from current period tax positions	3,300,000
Unrecognized tax benefits decrease resulting from settlements with taxing authorities	900,000
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months upper bound	22,200,000
General liability insurance claims deductible	10,000,000		10,000,000
Auto liability insurance claims deductible	10,000,000		10,000,000
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
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	1
Investments in Joint Ventures [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 17,800,000		19,100,000
Domestic Bank Accounts [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	19,700,000		127,200,000
Foreign Bank Accounts [Member]
Summary Of Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 29,500,000		$ 63,300,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment ownership	20.00%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Equity method investment ownership	50.00%
Percent change in contract estimates impact on operating results is less than this percentage	5.00%	5.00%

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Detail) - USD ($) $ in Thousands	Aug. 04, 2015	Sep. 30, 2015	Sep. 30, 2015
Discontinued Operations [Line Items]
Pretax gain on the disposal of the discontinued operations		$ 271,833	$ 271,833
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
Pretax gain on the disposal of the discontinued operations		272,000
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		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Major classes of line items constituting pretax income from fiber optic licensing operations:
Revenues	$ 8,736	$ 25,186	$ 59,998	$ 78,653
Cost of services (including depreciation)	3,037	9,118	24,748	29,329
Selling, general and administrative expenses	366	4,027	10,247	12,699
Amortization of intangible assets	138	413	963	1,238
Other income (expense) items that are not major		2	10	4
Net income before taxes of discontinued operations related to fiber optic licensing operations related to major classes of income before taxes	5,195	11,630	24,050	35,391
Pretax gain on the disposal of the discontinued operations	271,833		271,833
Total pretax gain on discontinued operations	277,028	11,630	295,883	35,391
Provision for income taxes	103,816	4,905	102,774	14,071
Net income from discontinued operations related to fiber optic licensing operations as presented in the statements of operations	$ 173,212	$ 6,725	$ 193,109	$ 21,320

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	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Accounts receivable		$ 11,429
Prepaid expenses and other current assets		11,287
Total current assets of fiber optic licensing operations		22,716
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	$ 147,148	21,091
Total current liabilities of fiber optic licensing operations	$ 147,148	21,091
Non-current liabilities:
Deferred income taxes		66,137
Long-term deferred revenue		48,231
Total major classes of non-current liabilities of fiber optic licensing operations		114,368
Other non-current liabilities of fiber optic licensing operations		193
Total non-current liabilities of fiber optic licensing operations		$ 114,561

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2015USD ($)Entity	Jun. 30, 2015Entity	Mar. 31, 2015Entity	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)Entityshares	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)Entityshares
Business Acquisition [Line Items]
Aggregate consideration for acquisitions						$ 98,941		$ 279,533
Number of shares granted for acquired companies | shares						461,037		686,382
Value of Quanta common stock and exchangeable shares issued						$ 10,100		$ 134,500
Estimated contingent consideration	$ 1,000					$ 1,000
Number of business acquisitions | Entity	4	3	3			10		9
Net tangible assets acquired				$ 71,100
Goodwill acquired				56,300		$ 49,554
Other intangible assets, acquired				45,100				$ 45,100
Fair value of accounts receivable acquired	$ 17,900			117,200		17,900		117,200
Goodwill expected to be deductible for income tax	30,100			$ 43,500		30,100		$ 43,500
Income (loss) from continuing operations before income taxes	78,133				$ 130,485	228,171	$ 330,056
2015 Acquisitions [Member]
Business Acquisition [Line Items]
Net tangible assets acquired						38,800
Goodwill acquired						49,600
Other intangible assets, acquired	21,700					21,700
Contributed by Acquisitions [Member]
Business Acquisition [Line Items]
Revenues	36,500					61,600
Income (loss) from continuing operations before income taxes	600					(600)
Acquisition costs	$ 1,900					$ 3,600
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						7
Electric Power Infrastructure Services Business [Member] | United States [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	2	2				4		1
Electric Power Infrastructure Services Business [Member] | Canada [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity		1	1			2		4
Electric Power Infrastructure Services Business [Member] | Australia [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity	1					1		1
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		1
Oil and Gas Infrastructure Services Business [Member] | Canada [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity			1			1		2
Oil and Gas Infrastructure Services Business [Member] | Australia [Member]
Business Acquisition [Line Items]
Number of business acquisitions | Entity			1			1
Electric Power Division [Member]
Business Acquisition [Line Items]
Goodwill acquired						$ 27,197		$ 72,300
Oil and Gas Infrastructure Division [Member]
Business Acquisition [Line Items]
Goodwill acquired						$ 22,357		$ 94,100

Acquisitions - Business Acquisi

Acquisitions - Business Acquisition Purchase Price Allocation Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Value of Quanta common stock and exchangeable shares issued	$ 10,100	$ 134,500
Cash paid or payable	98,941	279,533
Total identifiable net assets		45,100
Goodwill	1,596,931	1,596,695
All Acquisitions [Member]
Business Acquisition [Line Items]
Value of Quanta common stock and exchangeable shares issued	10,127	134,538
Cash paid or payable	98,941	279,533
Contingent consideration	1,001
Fair value of total consideration transferred or estimated to be transferred	110,069	414,071
Current assets	30,763	172,121
Property and equipment	42,839	159,186
Other assets	4	3,501
Identifiable intangible assets	21,668	96,302
Current liabilities	(22,317)	(145,646)
Deferred tax liabilities, net	(7,583)	(32,856)
Other long-term liabilities	(5,606)	(4,926)
Non-controlling interests	747
Total identifiable net assets	60,515	247,682
Goodwill	49,554	166,389
Fair value of total consideration transferred	$ 110,069	$ 414,071

Acquisitions - Estimated Fair V

Acquisitions - Estimated Fair Values of Identifiable Intangible Assets and Related Weighted Average Amortization (Detail) - Acquisitions [Member] $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 21,668
Weighted Average Amortization Period at Acquisition Date	10 years 7 months 6 days
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 13,856
Weighted Average Amortization Period at Acquisition Date	13 years 6 months
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 2,118
Weighted Average Amortization Period at Acquisition Date	1 year 1 month 6 days
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 3,752
Weighted Average Amortization Period at Acquisition Date	8 years 4 months 24 days
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value at Acquisition Date	$ 1,942
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	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Business Combinations [Abstract]
Revenues	$ 1,943,906	$ 2,316,002	$ 5,722,741	$ 6,313,290
Gross profit	236,364	353,021	713,434	920,610
Selling, general and administrative expenses	146,224	203,797	447,462	533,555
Amortization of intangible assets	8,694	11,868	26,230	34,745
Net income from continuing operations	46,032	96,598	137,039	235,320
Net income from continuing operations attributable to common stock	$ 43,464	$ 91,231	$ 126,314	$ 221,351
Earnings per share from continuing operations attributable to common stock - basic and diluted	$ 0.23	$ 0.41	$ 0.61	$ 0.99

Goodwill and Other Intangible38

Goodwill and Other Intangible Assets - Summary of Changes in Quanta's Goodwill (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2014	Sep. 30, 2015	Dec. 31, 2014
Goodwill [Line Items]
Goodwill, beginning balance		$ 1,596,695
Goodwill acquired	$ 56,300	49,554
Purchase price allocation adjustments		(8,113)
Foreign currency translation adjustments		(41,205)
Goodwill, ending balance	1,596,695	1,596,931	$ 1,596,695
Electric Power Division [Member]
Goodwill [Line Items]
Goodwill, beginning balance		1,223,224
Goodwill acquired		27,197	72,300
Purchase price allocation adjustments		750
Foreign currency translation adjustments		(23,811)
Goodwill, ending balance	1,223,224	1,227,360	1,223,224
Oil and Gas Infrastructure Division [Member]
Goodwill [Line Items]
Goodwill, beginning balance		373,471
Goodwill acquired		22,357	94,100
Purchase price allocation adjustments		(8,863)
Foreign currency translation adjustments		(17,394)
Goodwill, ending balance	$ 373,471	$ 369,571	$ 373,471

Goodwill and Other Intangible39

Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 470,346	$ 468,951
Accumulated Amortization	(244,933)	(225,367)
Intangible Assets, Net	$ 225,413	243,584
Remaining Weighted Average Amortization Period in Years	11 years
Customer Relationships [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 236,677	235,851
Accumulated Amortization	(75,235)	(63,764)
Intangible Assets, Net	$ 161,442	172,087
Remaining Weighted Average Amortization Period in Years	9 years 10 months 24 days
Backlog [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 131,312	133,704
Accumulated Amortization	(125,410)	(122,265)
Intangible Assets, Net	$ 5,902	11,439
Remaining Weighted Average Amortization Period in Years	10 months 24 days
Trade Names [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 51,298	49,664
Accumulated Amortization	(8,340)	(6,278)
Intangible Assets, Net	$ 42,958	43,386
Remaining Weighted Average Amortization Period in Years	18 years 9 months 18 days
Non-compete Agreements [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	$ 28,583	27,659
Accumulated Amortization	(22,633)	(21,365)
Intangible Assets, Net	$ 5,950	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	$ 22,476	22,073
Accumulated Amortization	(13,315)	(11,695)
Intangible Assets, Net	$ 9,161	$ 10,378
Remaining Weighted Average Amortization Period in Years	4 years 2 months 12 days

Goodwill and Other Intangible40

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 8,650	$ 9,125	$ 25,674	$ 25,160

Goodwill and Other Intangible41

Goodwill and Other Intangible Assets - Estimated Future Aggregate Amortization Expense of Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2015	$ 8,891
2,016	29,365
2,017	23,965
2,018	23,273
2,019	22,351
Thereafter	117,568
Intangible Assets, Net	$ 225,413	$ 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		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Amounts attributable to common stock:
Net income from continuing operations	$ 43,176	$ 87,923	$ 122,872	$ 208,818
Net income from discontinued operations	173,212	6,725	193,109	21,320
Net income attributable to common stock	$ 216,388	$ 94,648	$ 315,981	$ 230,138
Weighted average shares:
Weighted average shares outstanding for basic earnings per share	188,951	219,492	206,181	219,395
Effect of dilutive stock options	10	25	12	25
Weighted average shares outstanding for diluted earnings per share	188,961	219,517	206,193	219,420

Debt Obligations - Long-term De

Debt Obligations - Long-term Debt Obligations (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
Borrowings under credit facility	$ 339,159	$ 68,793
Other long-term debt, interest rates ranging from 1.4% to 4.3%	5,624	6,370
Capital leases, interest rates ranging from 6.0% to 7.3%	5,776	1,146
Total long-term debt obligations	350,559	76,309
Total long-term debt obligations	350,559	76,309
Less - Current maturities of long-term debt	2,350	3,820
Total long-term debt obligations, net of current maturities	$ 348,209	$ 72,489

Debt Obligations - Long-term 44

Debt Obligations - Long-term Debt Obligations (Parenthetical) (Detail)	Sep. 30, 2015	Dec. 31, 2014
Minimum [Member] | Other Long Term Debt [Member]
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	1.40%	1.40%
Minimum [Member] | Capital Leases [Member]
Debt Instrument [Line Items]
Capital leases and Other long-term debt interest rates	6.00%	6.00%
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	7.30%	7.30%

Debt Obligations - Current Matu

Debt Obligations - Current Maturities of Long-Term Debt and Short-Term Borrowings (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Short-term Debt [Abstract]
Short-term borrowings		$ 5,056
Current maturities of long-term debt	$ 2,350	3,820
Current maturities of long-term debt and short-term borrowings	$ 2,350	$ 8,876

Debt Obligations - Additional I

Debt Obligations - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Line of Credit Facility [Line Items]
Letters of credit and bank guarantees under the credit facility	$ 318,500,000
Amount borrowed under the credit facility	339,159,000	$ 68,793,000
Credit facility available for revolving loans or issuing new letters of credit	667,300,000
Letters Of Credit and Bank Guarantees [Member]
Line of Credit Facility [Line Items]
Letters of credit and bank guarantees under the credit facility	318,500,000
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	226,100,000
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	92,400,000
Borrowings Under Credit Facility [Member]
Line of Credit Facility [Line Items]
Amount borrowed under the credit facility	339,159,000
Borrowings Under Credit Facility [Member] | U S Dollar [Member]
Line of Credit Facility [Line Items]
Amount borrowed under the credit facility	241,500,000
Borrowings Under Credit Facility [Member] | Canadian Dollars [Member]
Line of Credit Facility [Line Items]
Amount borrowed under the credit facility	97,700,000
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	$ 75,000,000
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%
Prior and After April 1, 2014 [Member] | Second Amendment [Member]
Line of Credit Facility [Line Items]
Senior secured revolving credit facility	$ 1,325,000,000
Maturity date of senior secured revolving credit facility	Oct. 30, 2018
Option to increase revolving commitments under the credit agreement	$ 300,000,000
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	50,000,000
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	30,000,000
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	$ 20,000,000
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 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	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Line of Credit Facility [Abstract]
Maximum amount outstanding during the period	$ 470,560	$ 130,856	$ 470,560	$ 130,856
Average daily amount outstanding under the credit facility	$ 285,051	$ 35,129	$ 183,719	$ 19,743
Weighted-average interest rate	1.77%	2.75%	2.01%	2.71%

Equity - Additional Information

Equity - Additional Information (Detail) - USD ($)	Aug. 07, 2015	Dec. 31, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Feb. 28, 2017	Dec. 31, 2014
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			156,457,392		156,457,392			210,819,790
Exchangeable shares exchanged for common stock			449,929
Payments for repurchase of common stock			$ 1,175,293,000		$ 1,529,572,000	$ 45,021,000
Income attributable to the other joint venture members			2,600,000	$ 5,400,000	10,700,000	14,000,000
Carrying value of the investments held by Quanta in variable interest entities			14,500,000		14,500,000			$ 11,100,000
Non-controlling interests			14,542,000		14,542,000			$ 11,067,000
Distributions to non-controlling interests			$ 1,500,000	$ 3,000,000	6,500,000	$ 3,500,000
2013 Repurchase Program [Member]
Equity [Line Items]
Treasury stock acquired			1,800,000
Value of treasury stock acquired, cost method			$ 52,200,000
2013 Repurchase Program [Member] | Maximum [Member]
Equity [Line Items]
Aggregate authorized amount of common stock to be repurchased			500,000,000		500,000,000
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		$ 150,000,000
2015 Repurchase Plan Open Market Purchases [Member]
Equity [Line Items]
Treasury stock acquired			15,600,000
Value of treasury stock acquired, cost method			$ 373,100,000
2013 and 2015 Repurchase Program [Member]
Equity [Line Items]
Treasury stock acquired			43,100,000		55,700,000
Value of treasury stock acquired, cost method			$ 1,030,000,000		$ 1,380,000,000
Scenario Forecast [Member] | 2015 Repurchase Program [Member]
Equity [Line Items]
Treasury stock acquired		3,600,000
Value of treasury stock acquired, cost method		$ 76,800,000
Scenario Forecast [Member] | 2015 Repurchase Program [Member] | Maximum [Member]
Equity [Line Items]
Aggregate authorized amount of common stock to be repurchased							$ 1,250,000,000
Common Stock Withheld for Settlement of Employee Tax Liabilities [Member] | Treasury Stock [Member]
Equity [Line Items]
Treasury stock acquired					400,000	300,000
Value of treasury stock acquired, cost method					$ 10,100,000	$ 11,900,000
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
Series F- and Series G- Preferred Stock [Member]
Equity [Line Items]
Exchangeable stock shares outstanding			3,949,929		3,949,929

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
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		4,000,000
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		11,750,000
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	$ 0.7	$ 1.6	$ 3.2	$ 3.2
Payments to settle liabilities under compensation plan	1.2	$ 0.7	3.7	$ 2.9
Accrued liabilities under Compensation Plan	$ 2.4		$ 2.4		$ 2.9
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
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	100,000		1,300,000	1,400,000
Granted, weighted average grant date fair value, per share	$ 24.58	$ 36.28	$ 27.70	$ 35.13
Awards vested	100,000		1,200,000	1,000,000
Fair value of restricted stock, vested	$ 1.2	$ 1.2	$ 35	$ 36
Unrecognized compensation cost, related to unvested restricted stock, total	$ 38.7		$ 38.7
Expected weighted average period to recognize compensation cost on restricted stock and RSUs to be settled in stock (in years)			1 year 8 months 5 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
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, shares	0	0	200,000
Granted, weighted average grant date fair value, per share			$ 28.16
Awards vested	0	0	0	0
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.
Compensation costs	$ 1.1		$ 2.6
Number of common shares issued in connection with performance units	0	0	0	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%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	Oct. 09, 2013USD ($)	Dec. 31, 2014USD ($)Customer	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)Customerkm	Sep. 30, 2014USD ($)Customer	Sep. 30, 2015USD ($)CustomerAgencykm	Sep. 30, 2014USD ($)Customer	Dec. 31, 2014USD ($)Customer	Jul. 31, 2014USD ($)	Dec. 31, 2011USD ($)	Apr. 21, 2010mi
Commitment And Contingencies [Line Items]
Outstanding capital commitment						$ 8,500,000
Rent expense related to operating leases				$ 52,300,000	$ 38,000,000	152,500,000	$ 115,200,000
Maximum guaranteed residual value				$ 480,700,000		$ 480,700,000
Number of customers representing ten percent or more of consolidated revenues | Customer				0	0	0	0
Number of customers representing ten percent or more of net position | Customer		0		0		0		0
Gross amount accrued for insurance claims		$ 170,200,000		$ 194,600,000		$ 194,600,000		$ 170,200,000
Long-term insurance claims		130,800,000		150,600,000		150,600,000		130,800,000
Related insurance recoveries/receivables		9,100,000		8,700,000		8,700,000		9,100,000
Related insurance recoveries/receivables included in prepaid expenses and other current assets		800,000		500,000		500,000		800,000
Related insurance recoveries/receivables included in other assets net		8,300,000		8,200,000		8,200,000		$ 8,300,000
Letters of credit and bank guarantees under the credit facility				318,500,000		318,500,000
Total amount of outstanding performance bonds				2,400,000,000		2,400,000,000
Estimated cost to complete bonded projects				786,000,000		786,000,000
Multi-employer plan withdrawal obligation									$ 39,600,000	$ 32,600,000
Multi-employer plan withdrawal obligation, amount suggested by Plan which is different than amount recorded by company	$ 6,900,000
Multi-employer plan withdrawal obligation complete withdrawal	4,800,000
Multi-employer plan withdrawal obligation accrued						2,400,000
Cash proceeds deposited in Escrow account	$ 2,100,000
Pre-acquisition non-U.S.tax obligations and indemnification asset amount recorded				11,400,000		11,400,000
Pre-acquisition non-U.S.tax obligations and indemnification liability amount recorded				$ 11,400,000		$ 11,400,000
Alberta Power Line [Member]
Commitment And Contingencies [Line Items]
Length of electrical transmission line to be constructed under contract | km				500		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
Scenario Forecast [Member]
Commitment And Contingencies [Line Items]
Outstanding capital commitment			$ 1,200,000
June 1, 2017 [Member]
Commitment And Contingencies [Line Items]
Outstanding capital commitment						$ 7,300,000
Vehicle Fleet Committed Capital [Member]
Commitment And Contingencies [Line Items]
Estimated committed capital remainder of current year				$ 5,300,000		5,300,000
Estimated committed capital in 2016				500,000		500,000
Minimum [Member]
Commitment And Contingencies [Line Items]
Multi-employer plan withdrawal obligation				$ 40,100,000		$ 40,100,000
Minimum [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Commitment And Contingencies [Line Items]
Concentration risk percentage				10.00%	10.00%	10.00%	10.00%
Minimum [Member] | Net Position [Member] | Customer Concentration Risk [Member]
Commitment And Contingencies [Line Items]
Concentration risk percentage						10.00%		10.00%
Maximum [Member]
Commitment And Contingencies [Line Items]
Multi-employer plan withdrawal obligation				$ 55,400,000		$ 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 Contingencies51

Commitments and Contingencies - Outstanding Capital Commitments Associated with Investments in Unconsolidated Affiliates (Detail) - Corporate Joint Venture [Member] $ in Thousands	Sep. 30, 2015USD ($)
Other Commitments [Line Items]
Capital commitments, Remainder of 2015	$ 2,530
Capital commitments, 2016	8,010
Capital commitments, 2017	32,238
Capital commitments, 2018	0
Capital commitments, 2019	23,801
Capital commitments, thereafter	0
Total capital commitments associated with investments in unconsolidated affiliated related to an EPC electrical transmission project	$ 66,579

Commitments and Contingencies52

Commitments and Contingencies - Outstanding Capital Commitments Associated with Investments in Unconsolidated Affiliates (Parenthetical) (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)
Corporate Joint Venture [Member]
Other Commitments [Line Items]
Return of capital from unconsolidated affiliates anticipated for 2017	$ 42.5

Commitments and Contingencies53

Commitments and Contingencies - Minimum Lease Payments (Detail) $ in Thousands	Sep. 30, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
Remainder of 2015	$ 23,170
2,016	68,570
2,017	51,415
2,018	38,039
2,019	21,750
Thereafter	29,735
Total minimum lease payments	$ 232,679

Segment Information - Additiona

Segment Information - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)Segment	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			2
Property and equipment	$ 1,125,501		$ 1,125,501		$ 1,099,574
Canada [Member]
Segment Reporting Information [Line Items]
Percentage of foreign revenues	83.00%	83.00%	85.00%	81.00%
Foreign Operations [Member]
Segment Reporting Information [Line Items]
Revenues	$ 342,600	$ 523,700	$ 1,240,000	$ 1,370,000
Property and equipment	$ 337,200		$ 337,200		$ 372,900

Segment Information - Summarize

Segment Information - Summarized Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Revenues	$ 1,939,438	$ 2,145,958	$ 5,673,164	$ 5,719,615
Operating income (loss)	80,878	131,284	233,879	331,413
Depreciation	40,954	36,485	121,382	103,239
Electric Power Infrastructure [Member]
Segment Reporting Information [Line Items]
Revenues	1,183,151	1,396,157	3,645,767	3,938,590
Operating income (loss)	76,948	104,365	273,967	361,689
Depreciation	22,801	19,406	65,790	55,896
Oil and Gas Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Revenues	756,287	749,801	2,027,397	1,781,025
Operating income (loss)	58,874	74,824	119,002	109,235
Depreciation	16,347	15,146	49,599	41,826
Corporate and Non-Allocated Costs [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(54,944)	(47,905)	(159,090)	(139,511)
Depreciation	$ 1,806	$ 1,933	$ 5,993	$ 5,517

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) $ in Thousands	3 Months Ended				9 Months Ended	12 Months Ended
	Dec. 31, 2015USD ($)Entity	Sep. 30, 2015Entity	Jun. 30, 2015Entity	Mar. 31, 2015Entity	Sep. 30, 2015USD ($)Entity	Dec. 31, 2014USD ($)Entity
Subsequent Event [Line Items]
Number of business acquisitions		4	3	3	10	9
Cash paid or payable | $					$ 98,941	$ 279,533
Electric Power Infrastructure Services Business [Member]
Subsequent Event [Line Items]
Number of business acquisitions					7
Scenario Forecast [Member]
Subsequent Event [Line Items]
Cash paid or payable | $	$ 9,600
Scenario Forecast [Member] | Electric Power Infrastructure Services Business [Member]
Subsequent Event [Line Items]
Number of business acquisitions	1