Quanta Services (PWR) 10-Q 8 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 30, 2014
Document Information [Line Items]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'PWR	'
Entity Registrant Name	'QUANTA SERVICES INC	'
Entity Central Index Key	'0001050915	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	213,460,471
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	'	899,858

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current Assets:	'	'
Cash and cash equivalents	$273,340	$488,777
Accounts receivable, net of allowances of $5,186 and $5,215	1,501,857	1,439,115
Costs and estimated earnings in excess of billings on uncompleted contracts	274,966	213,478
Inventories	35,604	31,877
Prepaid expenses and other current assets	128,690	140,071
Total current assets	2,214,457	2,313,318
Property and equipment, net of accumulated depreciation of $657,326 and $631,939	1,269,656	1,205,608
Other assets, net	290,887	285,725
Other intangible assets, net of accumulated amortization of $230,712 and $223,355	219,573	207,877
Goodwill	1,832,047	1,780,717
Total assets	5,826,620	5,793,245
Current Liabilities:	'	'
Current maturities of long-term debt and notes payable	1,650	1,181
Accounts payable and accrued expenses	772,185	802,180
Billings in excess of costs and estimated earnings on uncompleted contracts	208,640	239,106
Total current liabilities	982,475	1,042,467
Long-term debt and notes payable, net of current maturities	4,556	1,053
Deferred income taxes	249,717	244,256
Insurance and other non-current liabilities	273,196	264,150
Total liabilities	1,509,944	1,551,926
Commitments and Contingencies	'	'
Equity:	'	'
Common stock, value	2	2
Additional paid-in capital	3,463,181	3,416,585
Retained earnings	1,124,485	1,070,077
Accumulated other comprehensive income (loss)	-55,219	-37,236
Treasury stock, 12,350,989 and 12,026,030 common shares, at cost	-226,644	-215,240
Total stockholders' equity	4,305,805	4,234,188
Noncontrolling interests	10,871	7,131
Total equity	4,316,676	4,241,319
Total liabilities and equity	5,826,620	5,793,245
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_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Allowances on accounts receivable, current	$5,186	$5,215
Accumulated depreciation on property and equipment	657,326	631,939
Accumulated amortization on other intangible assets	$230,712	$223,355
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	600,000,000	600,000,000
Common stock, shares issued	225,801,098	224,968,797
Common stock, shares outstanding	213,450,109	212,942,767
Treasury stock, common shares	12,350,989	12,026,030
Exchangeable Shares [Member]	'	'
Exchangeable Shares, par value	$0	$0
Common stock, shares issued	4,399,858	3,500,000
Common stock, shares outstanding	4,399,858	3,500,000
Series F Preferred Stock [Member]	'	'
Preferred stock, par value	$0.00	$0.00
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	$0.00	'
Preferred stock, shares authorized	1	0
Preferred stock, shares issued	1	0
Preferred stock, shares outstanding	1	0

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]	'	'
Revenues	$1,762,574	$1,585,710
Cost of services (including depreciation)	1,490,503	1,347,437
Gross profit	272,071	238,273
Selling, general and administrative expenses	173,331	113,681
Amortization of intangible assets	8,245	5,301
Operating income	90,495	119,291
Interest expense	-982	-502
Interest income	1,545	522
Other income (expense), net	643	-513
Income before income taxes	91,701	118,798
Provision for income taxes	33,053	41,941
Net income	58,648	76,857
Less: Net income attributable to noncontrolling interests	4,240	4,776
Net income attributable to common stock	$54,408	$72,081
Earnings per share attributable to common stock - basic and diluted	$0.25	$0.34
Shares used in computing earnings per share:	'	'
Weighted average basic shares outstanding	219,033	213,453
Weighted average diluted shares outstanding	219,075	213,512

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Net income	$58,648	$76,857
Other comprehensive income (loss), net of tax provision:	'	'
Foreign currency translation adjustment, net of tax of $0 and $0	-17,965	-13,743
Other, net of tax of $6 and $0	-18	'
Other comprehensive income (loss)	-17,983	-13,743
Comprehensive income	40,665	63,114
Less: Comprehensive income attributable to noncontrolling interests	4,240	4,776
Total comprehensive income attributable to Quanta stockholders	$36,425	$58,338

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Foreign currency translation adjustment, tax	$0	$0
Other comprehensive income other tax	$6	$0

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash Flows from Operating Activities:	'	'
Net income	$58,648	$76,857
Adjustments to reconcile net income to net cash provided by (used in) operating activities -	'	'
Depreciation	36,865	31,880
Amortization of intangible assets	8,245	5,301
Amortization of debt issuance costs	275	218
Amortization of deferred revenues	-2,746	-2,505
Gain on sale of property and equipment	-305	-282
Foreign currency (gain) loss	-266	502
Provision for doubtful accounts	48	1,508
Non-cash portion of arbitration expense	10,518	'
Deferred income tax provision (benefit)	8,086	-1,122
Non-cash stock-based compensation	10,298	8,036
Tax impact of stock-based equity awards	-123	'
Changes in operating assets and liabilities, net of non-cash transactions -	'	'
Accounts and notes receivable	-61,480	30,843
Costs and estimated earnings in excess of billings on uncompleted contracts	-46,946	-65,030
Inventories	-1,923	497
Prepaid expenses and other current assets	-368	13,548
Accounts payable and accrued expenses and other non-current liabilities	-50,999	-47,634
Billings in excess of costs and estimated earnings on uncompleted contracts	-31,632	-10,504
Other, net	3,272	2,019
Net cash provided by (used in) operating activities	-60,533	44,132
Cash Flows from Investing Activities:	'	'
Proceeds from sale of property and equipment	2,493	1,544
Additions of property and equipment	-71,418	-57,637
Cash paid for acquisitions, net of cash acquired	-76,368	-977
Investments in and return on equity from unconsolidated affiliates	'	-8,545
Cash received from (paid for) other investments	259	'
Net cash used in investing activities	-145,034	-65,615
Cash Flows from Financing Activities:	'	'
Borrowings under credit facility	2,370	'
Payments under credit facility	-2,370	'
Payments on other long-term debt	-10,293	'
Distributions to noncontrolling interests	-500	-5,454
Tax impact of stock-based equity awards	123	'
Exercise of stock options	424	497
Net cash used in financing activities	-10,246	-4,957
Effect of foreign exchange rate changes on cash and cash equivalents	376	-1,642
Net decrease in cash and cash equivalents	-215,437	-28,082
Cash and cash equivalents, beginning of period	488,777	394,701
Cash and cash equivalents, end of period	273,340	366,619
Supplemental disclosure of cash flow information:	'	'
Interest paid	-1,268	-462
Income taxes paid	-87,712	-91,581
Income tax refunds	$238	$6

Business_and_Organization

Business and Organization	3 Months Ended
	Mar. 31, 2014
Accounting Policies [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 North America and in select international markets. Quanta reports its results under three reportable segments: (1) Electric Power Infrastructure Services, (2) Oil and Gas Infrastructure Services and (3) Fiber Optic Licensing and Other.
	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 design, installation, maintenance and repair of commercial and industrial wiring, installation of traffic networks and the installation of cable and control systems for light rail lines.
	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, 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 airport fueling systems as well as water and sewer infrastructure.
	Fiber Optic Licensing and Other Segment
	The Fiber Optic Licensing and Other segment designs, procures, constructs, maintains and owns fiber optic telecommunications infrastructure in select markets and licenses the right to use these point-to-point fiber optic telecommunications facilities to its customers pursuant to licensing agreements, typically with terms from five to twenty-five years, inclusive of certain renewal options. Under these agreements, customers are provided the right to use a portion of the capacity of a fiber optic network, with the network owned and maintained by Quanta. Additionally, the Fiber Optic Licensing and Other segment provides lit services, with Quanta providing network management services to customers as well as owning the electronic equipment necessary to make the fiber optic network operational. This segment serves customers in multiple institutional sectors, including communications carriers as well as education, financial services, healthcare and other business enterprises with high bandwidth telecommunication needs. The telecommunication services provided through this segment are subject to regulation by the Federal Communications Commission and certain state public utility commissions. The Fiber Optic Licensing and Other segment also provides various telecommunication infrastructure services on a limited and ancillary basis, primarily to Quanta’s customers in the electric power industry.
	Acquisitions
	During the first quarter of 2014, Quanta completed five acquisitions. Four of these five companies are electric power infrastructure services companies located in Canada. The fifth company is a general engineering and construction company, based in California, specializing in hydrant fueling, waterfront and utility construction for U.S. Department of Defense military bases, and is generally included in Quanta’s Oil and Gas Infrastructure Services segment. During 2013, Quanta acquired six businesses, which included electric power infrastructure services companies and oil and gas infrastructure services companies based in the U.S., Canada and Australia.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
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 20% to 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 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, 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, 2013, which was filed with the SEC on March 3, 2014.
	Use of Estimates and Assumptions
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States 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 amount 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, multi-employer pension plan withdrawal liabilities, revenue recognition for construction contracts and fiber optic licensing, share-based compensation, operating results of reportable segments, as well as the provision for income taxes and the calculation of uncertain tax positions.
	Reclassifications
	Certain reclassifications have been made to prior year’s balance sheet to conform to classifications used in the current year.
	Cash and Cash Equivalents
	Quanta had cash and cash equivalents of $273.3 million and $488.8 million as of March 31, 2014 and December 31, 2013. Cash consisting of interest-bearing demand deposits is carried at cost, which approximates fair value. Quanta considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents, which are carried at fair value. At March 31, 2014 and December 31, 2013, cash equivalents were $66.5 million and $247.8 million, which consisted primarily of money market mutual funds and are discussed further in “Fair Value Measurements” below. As of March 31, 2014 and December 31, 2013, cash and cash equivalents held in domestic bank accounts were approximately $134.1 million and $236.7 million, and cash and cash equivalents held in foreign bank accounts were approximately $139.2 million and $252.1 million.
	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 including, among others, the customer’s access to capital, the customer’s willingness or ability to pay, general economic and market conditions and the ongoing relationship with the customer. 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 March 31, 2014 and December 31, 2013, Quanta had total allowances for doubtful accounts of approximately $5.2 million, all of which were included as a reduction of net current accounts receivable. 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 March 31, 2014 and December 31, 2013 were approximately $194.6 million and $194.5 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 March 31, 2014 and December 31, 2013 were $55.6 million and $50.8 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 March 31, 2014 and December 31, 2013, the balances of unbilled receivables included in accounts receivable were approximately $211.9 million and $179.2 million.
	Goodwill and Other Intangibles
	Quanta has recorded goodwill in connection with its historical acquisitions of companies. Upon acquisition, these companies have been 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 three internal divisions: the Electric Power Division, the Oil and Gas Infrastructure Division or the Fiber Optic Licensing 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 operating segment level or one level below the operating segment level for which discrete financial information is available, and 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 performing 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 2013, 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 2013 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, 2013 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.
	Quanta’s intangible assets include customer relationships, backlog, trade names, non-compete agreements, patented rights and developed technology, all subject to amortization, along with other intangible assets not 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, 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 finance 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 noncontrolling 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 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
	Infrastructure Services — 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 three months ended March 31, 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, 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 March 31, 2014 and December 31, 2013, Quanta had approximately $247.2 million and $241.8 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. The March 31, 2014 and December 31, 2013 balances of recognized change orders and claims included a change order from the Sunrise Powerlink project, an electric power infrastructure services project, primarily as a result of multiple customer-directed changes to the construction schedule which required PAR Electrical Contractors, Inc. (PAR), a wholly-owned subsidiary of Quanta, to significantly increase its resources to the project in order to meet the customer required completion date. Revenues of approximately $165 million associated with this change order were accrued and recognized as a component of costs and estimated earnings in excess of billings on uncompleted contracts in prior years. Following completion of the project, PAR and its customer, San Diego Gas & Electric Company (SDG&E), had ongoing meetings to review project scope, costs and performance criteria in order to reach resolution on the additional work performed and pricing of the change order under the contract, which resulted in PAR and SDG&E being in agreement as to PAR’s direct costs incurred in completing the project. Although the parties agreed upon PAR’s direct costs, the parties have been unsuccessful in agreeing on the final amount owed to PAR. As a result, PAR initiated arbitration proceedings in the fourth quarter of 2013 pursuant to a contractually agreed upon dispute resolution process. See Legal Proceedings - Sunrise Powerlink Arbitration in Note 10 for additional information. Quanta reclassified the recognized balance related to this contract from costs and estimated earnings in excess of billings on uncompleted contracts into other assets, net as this process is not expected to conclude within the next twelve months. As of March 31, 2014, no interest has been accrued related to this long-term receivable since the arbitration process is still ongoing. The aggregate contract price adjustments discussed above 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. Although Quanta believes that it is entitled to the amount PAR is seeking in the matter related to the Sunrise Powerlink project, due to the nature of those proceedings, an adverse result in that matter could have a material adverse effect on Quanta’s consolidated financial condition, results of operations and cash flows.
	Fiber Optic Licensing — The fiber optic licensing business constructs and licenses the right to use fiber optic telecommunications facilities to its customers pursuant to licensing agreements, typically with terms from five to twenty-five years, inclusive of certain renewal options. Under those agreements, customers are provided the right to use a portion of the capacity of a fiber optic facility, with the facility owned and maintained by Quanta. Revenues, including any initial fees or advance billings, are recognized ratably over the expected length of the agreements, including probable renewal periods. As of March 31, 2014 and December 31, 2013, initial fees and advance billings on these licensing agreements not yet recorded in revenue were $49.7 million and $48.8 million and are recognized as deferred revenue, with $41.6 million and $40.2 million considered to be long-term and included in other non-current liabilities. Minimum future licensing revenues expected to be recognized by Quanta pursuant to these agreements at March 31, 2014 were as follows (in thousands):
			Minimum Future
			Licensing
			Revenues
	Year Ending December 31 —
	Remainder of 2014		$	61,418
	2015			57,394
	2016			47,581
	2017			38,096
	2018			28,080
	Thereafter			133,227
	Fixed non-cancelable minimum licensing revenues		$	365,796
	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 March 31, 2014, the total amount of unrecognized tax benefits relating to uncertain tax positions was $51.2 million, an increase from December 31, 2013 of $2.4 million. This increase in unrecognized tax benefits is primarily due to tax positions expected to be taken for 2014. Certain subsidiaries are under examination by various U.S. state and Canadian federal tax authorities for multiple periods. Quanta believes that it is reasonably possible that within the next 12 months unrecognized tax benefits may decrease up to $11.0 million as a result of settlement of these audits 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.
	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 any 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 and restricted stock units (RSUs) to be settled in common stock based on the fair value of the awards granted, net of estimated forfeitures, at the date of grant. The fair value of restricted stock awards and RSUs to be settled in common stock is determined based on the number of shares or RSUs 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. Restricted stock awards and RSUs to be settled in common stock are subject to forfeiture, restrictions on transfer and certain other conditions until vesting. During the restriction period, holders of restricted stock are entitled to vote and receive dividends on such shares. The cash flows resulting from the tax deductions in excess of the compensation expense recognized for restricted stock, RSUs 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 be settled in cash, is recognized based on a remeasurement of the fair value of the award at the end of each reporting period. RSUs to be settled in cash are intended to provide the holders with cash performance incentives that are substantially equivalent to the risks and rewards of equity ownership in Quanta. RSUs to be settled in cash 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. Upon vesting of RSUs to be settled in cash, the holders receive for each vested RSU an amount in cash equal to the fair market value on the vesting date of one share of Quanta common stock, as specified in the applicable award agreement.
	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. Under the relevant accounting guidance, 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 (loss) and cash flows are translated at average monthly rates, while balance sheets are translated at the month-end exchange rates. The translation of the balance sheets at the month-end exchange rates results in translation gains or losses. If transactions are denominated in the operating units’ functional currency, the translation gains and losses are included as a separate component of equity under the caption “Accumulated other comprehensive income (loss).” If transactions are not denominated in the operating units’ functional currency, the translation gains and losses are included within the statement of operations.
	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), net of tax, 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
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 10.
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. 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 March 31, 2014 and December 31, 2013, 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. The level of inputs used for these fair value measurements is the lowest level (Level 3). Quanta believes that these valuation methods appropriately represent the methods that would be used by other market participants in determining fair value.
Quanta uses fair value measurements on a routine basis in its assessment of assets classified as goodwill, other intangible assets and long-lived assets held and used. In accordance with its annual impairment test during the quarter ended December 31, 2013, the carrying amounts of such assets, including goodwill, were compared to their fair values. The inputs used for fair value measurements for goodwill, other intangible assets and long-lived assets held and used are the lowest level (Level 3) inputs, and Quanta uses the assistance of third party specialists to develop valuation assumptions.
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.

New_Accounting_Pronouncements

New Accounting Pronouncements	3 Months Ended
	Mar. 31, 2014
Accounting Changes And Error Corrections [Abstract]	'
New Accounting Pronouncements	'
	3	NEW ACCOUNTING PRONOUNCEMENTS:
	Adoption of New Accounting Pronouncements
	On January 1, 2014, Quanta adopted an update that provides guidance on the balance sheet presentation of an unrecognized tax benefit when a net operating loss carryforward, similar tax loss, or tax credit carryforward exists as of the reporting date. The update is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. The impact of the adoption of this standard did not have a material effect on Quanta’s consolidated financial statements.
	Accounting Standards Not Yet Adopted
	In April of 2014, the 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. The update is effective prospectively for fiscal years beginning on or after December 15, 2014 and interim periods within those years. Early adoption is permitted, but only for disposals (or classifications as held for sale) that have not been reported in previously issued financial statements. 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, 2015.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	4	ACQUISITIONS:
	2014 Acquisitions
	During the first quarter of 2014, Quanta completed five acquisitions. Four of these five companies are electric power infrastructure services companies located in Canada. The fifth company is a general engineering and construction company, based in California, specializing in hydrant fueling, waterfront and utility construction for the U.S. Department of Defense and is generally included in Quanta’s Oil and Gas Infrastructure Services segment. The aggregate consideration paid for these acquisitions consisted of approximately $79.9 million in cash, 393,052 shares of Quanta common stock and 899,858 exchangeable shares of a Canadian subsidiary of Quanta that are substantially equivalent to, and exchangeable on a one-for-one basis for, Quanta common stock. In addition, Quanta issued one share of Series G preferred stock with voting rights equivalent to Quanta common stock equal to the number of exchangeable shares outstanding at any time. The aggregate value of the above issued securities on the respective closing dates of the acquisitions totaled approximately $36.6 million. As these transactions were effective during the first quarter of 2014, the results are 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 infrastructure service offerings in Canada and its oil and gas infrastructure service offerings in the U.S.
	2013 Acquisitions
	During 2013, Quanta acquired six businesses, which included electric power infrastructure services companies and oil and gas infrastructure services companies based in the U.S., Canada and Australia. The aggregate consideration paid for these acquisitions consisted of approximately $341.1 million in cash and 3,547,482 shares of Quanta common stock valued, as of the respective dates of issuance, at approximately $88.9 million. The results for each company have been included in Quanta’s consolidated financial statements beginning on the respective dates of acquisition. These acquisitions have enabled Quanta to further enhance its electric power infrastructure service and oil and gas infrastructure service offerings in the United States and select international markets.
	The following table summarizes the aggregate consideration paid through March 31, 2014 for the 2014 and 2013 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).
			2014			2013
	Consideration:
	Value of Quanta common stock and exchangeable shares issued		$	36,604		$	88,895
	Cash paid			79,927			341,064
	Fair value of total consideration transferred		$	116,531		$	429,959
	Current assets		$	52,986		$	193,895
	Property and equipment			33,387			60,988
	Other assets			3,373			1,009
	Identifiable intangible assets			21,048			55,124
	Current liabilities			(41,281	)		(127,430	)
	Deferred tax liabilities, net			(3,692	)		(4,083	)
	Other long-term liabilities			(3,935	)		(5,350	)
	Total identifiable net assets			61,886			174,153
	Goodwill			54,645			255,806
			$	116,531		$	429,959
	The fair value of current assets acquired in 2014 included accounts receivable with a fair value of $31.1 million. The fair value of current assets acquired in 2013 included accounts receivable with a fair value of $83.9 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 2014 and 2013 acquisitions strategically expanded Quanta’s Canadian and Australian service offerings and enhanced its domestic electric power and oil and gas service offerings, which Quanta believes contributes to the recognition of the goodwill. In connection with the 2014 acquisitions, goodwill of $47.0 million was recorded for reporting units included within Quanta’s electric power division and $7.6 million was recorded for reporting units included within Quanta’s oil and gas infrastructure division at March 31, 2014. In connection with the 2013 acquisitions, goodwill of $112.5 million was recorded for reporting units included within Quanta’s electric power division and $143.3 million was recorded for reporting units included within Quanta’s oil and gas infrastructure division at December 31, 2013. Goodwill of approximately $7.6 million and $213.6 million is expected to be deductible for income tax purposes related to the businesses acquired in 2014 and 2013.
	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
			March 31,
			2014			2013
	Revenues		$	1,766,756		$	1,785,809
	Gross profit		$	271,736		$	277,641
	Selling, general and administrative expenses		$	174,359		$	128,020
	Amortization of intangible assets		$	8,326		$	9,236
	Net income		$	57,675		$	89,915
	Net income attributable to common stock		$	53,435		$	85,139
	Earnings per share attributable to common stock - basic and diluted		$	0.24		$	0.39
	The pro forma combined results of operations for the three months ended March 31, 2014 and 2013 have been prepared by adjusting the historical results of Quanta to include the historical results of the 2014 acquisitions as if they occurred January 1, 2013. The pro forma combined results of operations for the three months ended March 31, 2013 have also been prepared by adjusting the historical results of Quanta to include the historical results of the 2013 acquisitions as if they occurred January 1, 2012. These pro forma combined historical results were then adjusted for the following: a reduction of interest expense and interest income as a result of the repayment of outstanding indebtedness, 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 2014 and 2013 acquisitions, an increase or decrease in depreciation expense within cost of services related to the net impact of adjusting acquired property and equipment to the acquisition date fair value and conforming depreciable lives with Quanta’s accounting policies, an increase in the number of outstanding shares of Quanta common stock and 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 2014 and 2013 acquisitions. As noted above, the pro forma results of operations do not purport to be indicative of the actual results that would have been achieved by the combined company for the periods presented or that may be achieved by the combined company in the future.
	Revenues of approximately $37.0 million and income (loss) before income taxes of approximately $(0.1) million, which includes $4.2 million of acquisition costs, were included in Quanta’s consolidated results of operations for the three months ended March 31, 2014 related to the 2014 acquisitions following their respective dates of acquisition.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	3 Months Ended
	Mar. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]	'
Goodwill and Other Intangible Assets	'
	5	GOODWILL AND OTHER INTANGIBLE ASSETS:
	A summary of changes in Quanta’s goodwill is as follows (in thousands):
			Electric Power			Oil and Gas			Fiber Optic			Total
			Division			Infrastructure			Licensing
						Division			Division
	Goodwill balance at December 31, 2013		$	1,168,084		$	277,843		$	334,790		$	1,780,717
	Goodwill acquired during 2014			47,089			7,556			—			54,645
	Foreign currency translation related to goodwill			(5,261	)		1,946			—			(3,315	)
	Goodwill balance at March 31, 2014		$	1,209,912		$	287,345		$	334,790		$	1,832,047
	As described in Note 2, Quanta’s operating units are organized into one of Quanta’s three 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.
	Activity in Quanta’s intangible assets consisted of the following (in thousands):
			As of						Three Months Ended									As of
			December 31, 2013						March 31, 2014									March 31, 2014
			Intangible			Accumulated			Amortization			Additions			Foreign			Intangible		Remaining
			Assets			Amortization			Expense						Currency			Assets, Net		Weighted
															Adjustments					Average
																				Amortization
																				Period in Years
	Customer relationships		$	199,224		$	(59,417	)	$	(3,650	)	$	11,131		$	195		$	147,483		10.6
	Backlog			136,831			(127,233	)		(2,957	)		4,908			730			12,279		0.9
	Trade names			40,342			(4,228	)		(466	)		3,917			(1,954	)		37,611		22.7
	Non-compete agreements			28,895			(22,861	)		(652	)		688			(71	)		5,999		3.3
	Patented rights and developed technology			21,440			(9,616	)		(520	)		404			(7	)		11,701		5.1
	Total intangible assets subject to amortization			426,732			(223,355	)		(8,245	)		21,048			(1,107	)		215,073		11.6
	Other intangible assets not subject to amortization			4,500			—			—			—			—			4,500		N/A
	Total intangible assets		$	431,232		$	(223,355	)	$	(8,245	)	$	21,048		$	(1,107	)	$	219,573		N/A
	Amortization expense for intangible assets was $8.2 million and $5.3 million for the three months ended March 31, 2014 and 2013. The estimated future aggregate amortization expense of intangible assets as of March 31, 2014 is set forth below (in thousands):
	For the Fiscal Year Ending December 31,
	Remainder of 2014		$	25,088
	2015			21,875
	2016			20,503
	2017			19,043
	2018			18,776
	Thereafter			109,788
	Total		$	215,073

Per_Share_Information

Per Share Information	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Per Share Information	'
	6	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 months ended March 31, 2014 and 2013 are illustrated below (in thousands):
			Three Months Ended
			March 31,
			2014		2013
	AMOUNTS ATTRIBUTABLE TO COMMON STOCK:
	Net income attributable to common stock		$	54,408	$	72,081
	WEIGHTED AVERAGE SHARES:
	Weighted average shares outstanding for basic earnings per share			219,033		213,453
	Effect of dilutive stock options			42		59
	Weighted average shares outstanding for diluted earnings per share			219,075		213,512
	For purposes of calculating diluted earnings per share, there were no adjustments required to derive Quanta’s net income attributable to common stock. The outstanding exchangeable shares of a Canadian subsidiary of Quanta that were issued pursuant to the acquisition of Valard Construction LP and certain of its affiliated entities (Valard) on October 25, 2010, 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 months ended March 31, 2014 and 2013. Additionally, the outstanding exchangeable shares of a Canadian subsidiary of Quanta that were issued pursuant to the acquisition of Northstar Energy Services Inc. and Northstar Transport Services Inc. (Northstar) on January 14, 2014, which are also 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 months ended March 31, 2014, weighted for the portion of the period they were outstanding.

Debt_Obligations

Debt Obligations	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Debt Obligations	'
	7	DEBT OBLIGATIONS:
	Credit Facility
	On October 30, 2013, Quanta entered into a credit agreement which amended and restated its prior facility with various lenders. The credit agreement provides for a $1.325 billion senior secured revolving credit facility maturing October 30, 2018. Up to $400.0 million of the facility is available for revolving loans and letters of credit in certain alternative currencies in addition to the U.S. dollar. The entire amount of the facility is available for the issuance of letters of credit. Up to $50.0 million of the facility is available for swing line loans in U.S. dollars, up to $30.0 million of the facility is available for swing line loans in Canadian dollars and up to $20.0 million of the facility is available for swing line loans in Australian dollars. In addition, subject to the conditions specified in the credit agreement, Quanta has the option to increase the revolving commitments under the credit agreement by up to an additional $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 March 31, 2014, Quanta had approximately $213.5 million of letters of credit issued, $186.7 million of which was denominated in U.S. dollars and $26.8 million of which was denominated in Australian or Canadian dollars, and no outstanding borrowings under the credit facility. The remaining $1.11 billion was available for borrowings or issuing new letters of credit.
	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 (a) the Eurocurrency Rate (as defined in the credit agreement) plus 1.25%, or (b) the Base Rate (as described below) 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 (as defined in the credit agreement) issued under the credit agreement in support of certain contractual obligations were subject to a letter of credit fee of 0.75%. Quanta was also subject to a commitment fee of 0.20% on any unused availability under the credit agreement.
	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 (a) the Eurocurrency Rate plus 1.125% to 2.125%, as determined based on Quanta’s Consolidated Leverage Ratio (as described below), or (b) the Base Rate 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 issued under the credit agreement in support of certain contractual obligations are subject to a letter of credit fee of 0.675% to 1.275%, based on Quanta’s Consolidated Leverage Ratio. Quanta is also subject to a commitment fee of 0.20% to 0.40%, based on its Consolidated Leverage Ratio, on any unused availability under the credit agreement.
	The Consolidated Leverage Ratio is the ratio of Quanta’s Consolidated Funded Indebtedness to Consolidated EBITDA (as defined in the credit agreement). For purposes of calculating the 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 1/2 of 1%, (ii) Bank of America’s prime rate and (iii) the Eurocurrency Rate plus 1.00%.
	Subject to certain exceptions, the credit agreement is secured by substantially all of the assets of Quanta and its 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 Quanta’s 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, 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.), all collateral will automatically be released from these liens.
	The credit agreement contains certain covenants, including a maximum Consolidated Leverage Ratio and a Consolidated Interest Coverage Ratio, in each case as specified in the credit agreement. The credit agreement limits certain acquisitions, mergers and consolidations, indebtedness, asset sales and prepayments of indebtedness and, subject to certain exceptions, prohibits liens on assets. The credit agreement also allows for cash payments for dividends and stock repurchases subject to compliance with the following requirements on a post-incurrence basis: (i) no default or event of default under the credit agreement; (ii) continued compliance with the financial covenants described above; and (iii) at least $100 million of availability under the credit agreement and/or cash and cash equivalents on hand. As of March 31, 2014, Quanta was in compliance with all of the covenants in the credit agreement.
	The credit agreement provides for customary events of default and carries cross-default provisions with Quanta’s underwriting, continuing indemnity and security agreement with its sureties and all of its 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, amounts outstanding under the credit agreement may be accelerated and may become or be declared immediately due and payable.
	Between April 2, 2011 and October 30, 2013, Quanta had a credit agreement that provided for a $700.0 million senior secured revolving credit facility with a maturity date of August 2, 2016. Borrowings under the credit agreement were to be used to refinance existing indebtedness and for working capital, capital expenditures and other general corporate purposes. Quanta entered into the credit agreement on August 2, 2011, which amended and restated its prior credit agreement.
	Amounts borrowed under the credit agreement in U.S. dollars bore interest, at Quanta’s option, at a rate equal to either (a) the Eurocurrency Rate (as defined in the credit agreement) plus 1.25% to 2.50%, as determined based on Quanta’s Consolidated Leverage Ratio (as described below), plus, if applicable, any Mandatory Cost (as defined in the credit agreement) required to compensate lenders for the cost of compliance with certain European regulatory requirements, or (b) the Base Rate (as described below) plus 0.25% to 1.50%, as determined based on Quanta’s Consolidated Leverage Ratio. Amounts borrowed 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% to 2.50%, as determined based on Quanta’s Consolidated Leverage Ratio, plus, if applicable, any Mandatory Cost. Standby letters of credit issued under the credit agreement were subject to a letter of credit fee of 1.25% to 2.50%, based on Quanta’s Consolidated Leverage Ratio, and Performance Letters of Credit (as defined in the credit agreement) issued under the credit agreement in support of certain contractual obligations were subject to a letter of credit fee of 0.75% to 1.50%, based on Quanta’s Consolidated Leverage Ratio. Quanta was also subject to a commitment fee of 0.20% to 0.45%, based on Quanta’s Consolidated Leverage Ratio, on any unused availability under the credit agreement. The Consolidated Leverage Ratio was the ratio of Quanta’s total funded debt to Consolidated EBITDA (as defined in the credit agreement). For purposes of calculating both the Consolidated Leverage Ratio and the maximum senior debt to Consolidated EBITDA ratio discussed below, total funded debt and total senior debt were reduced by all unrestricted cash and Cash Equivalents (as defined in the credit agreement) held by Quanta in excess of $25.0 million. The Base Rate equaled the highest of (i) the Federal Funds Rate (as defined in the credit agreement) plus 1/2 of 1%, (ii) Bank of America’s prime rate and (iii) the Eurocurrency Rate plus 1.00%.

Equity

Equity	3 Months Ended
	Mar. 31, 2014
Equity [Abstract]	'
Equity	'
	8	EQUITY:
	Exchangeable Shares and Series F and Series G Preferred Stock
	In connection with the acquisition of Valard on October 25, 2010, certain former owners of Valard received exchangeable shares of a Canadian subsidiary of Quanta which may be exchanged at the option of the holder 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. Quanta also issued one share of Quanta Series F preferred stock to a voting trust on behalf of the holders of the exchangeable shares. The Quanta Series F preferred stock provides the holders of the exchangeable shares voting rights in Quanta common stock equivalent to the number of exchangeable shares outstanding at any time. The combination of the exchangeable shares and the share of Quanta Series F preferred stock gives the holders of the exchangeable shares rights equivalent to Quanta common stockholders with respect to dividends, voting and other economic rights. On March 26, 2013, 409,110 exchangeable shares were exchanged for Quanta common stock.
	In connection with the acquisition of Northstar on January 14, 2014, the former owner of Northstar received exchangeable shares of a Canadian subsidiary of Quanta which may be exchanged at the option of the holder for Quanta common stock on a one-for-one basis. The holder of the 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. Quanta also issued one share of Quanta Series G preferred stock to the holder of the exchangeable shares. The Quanta Series G preferred stock provides the holder of the exchangeable shares voting rights in Quanta common stock equivalent to the number of exchangeable shares outstanding at any time. The combination of the exchangeable shares and the share of Quanta Series G preferred stock gives the holder of the exchangeable shares rights equivalent to Quanta common stockholders with respect to dividends, voting and other economic rights.
	Treasury Stock
	Under the stock incentive plans described in Note 9, 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. As a result, Quanta withheld 324,959 and 296,874 shares of Quanta common stock during the three months ended March 31, 2014 and 2013, with a total market value of $11.4 million and $9.7 million, in each case for settlement of employee tax liabilities. These shares and the related cost to acquire them were accounted for as an adjustment 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, up to $500.0 million of its outstanding common stock through December 31, 2016. As of March 31, 2014, there had been no repurchases under this plan. The shares and the related cost to acquire them will be accounted for as an adjustment to the balance of treasury stock.
	Noncontrolling Interests
	Quanta holds investments in several joint ventures that provide infrastructure services under specific customer contracts. Typically, each joint venture is owned equally by its members. Quanta has determined that certain of these joint ventures are variable interest entities, 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 these joint ventures and has accounted for each on a consolidated basis. The other parties’ equity interests in these joint ventures have been accounted for as noncontrolling interests in the condensed consolidated financial statements. Income attributable to the other joint venture members has been accounted for as a reduction to net income in order to obtain net income attributable to common stock in the amount of $4.2 million and $4.8 million for the three months ended March 31, 2014 and 2013. 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 noncontrolling interests within total equity in the accompanying balance sheets.
	The carrying value of the investments held by Quanta in all of its variable interest entities was approximately $10.9 million and $7.1 million at March 31, 2014 and December 31, 2013. The carrying value of investments held by the noncontrolling interests in these variable interest entities at March 31, 2014 and December 31, 2013 was $10.9 million and $7.1 million. During the three months ended March 31, 2014 and 2013, distributions to noncontrolling interests were $0.5 million and $5.5 million. There were no other changes in equity as a result of transfers to/from the noncontrolling interests during the three months ended March 31, 2014 or 2013. See Note 10 for further disclosures related to Quanta’s joint venture arrangements.

EquityBased_Compensation

Equity-Based Compensation	3 Months Ended
	Mar. 31, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Equity-Based Compensation	'
	9	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 (ISOs), stock appreciation rights, restricted stock, RSUs, stock bonus awards, performance compensation awards (including 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 each of the three months ended March 31, 2014 and 2013, Quanta granted 1.3 million shares of restricted stock and RSUs to be settled in common stock under the Plans. 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 March 31, 2014 and 2013, vesting activity consisted of 1.0 million and 0.9 million shares of restricted stock and RSUs settled in common stock with an approximate fair value at the time of vesting of $33.5 million and $24.3 million.
	As of March 31, 2014, there was approximately $54.5 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 2.26 years.
	RSUs To Be Settled in Cash
	Certain RSUs granted by Quanta under the Plans are intended to provide plan participants with cash performance incentives that are substantially equivalent to the risks and rewards of equity ownership in Quanta. These RSUs to be settled in cash 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. Upon vesting of these RSUs, the holders receive for each vested RSU an amount in cash equal to the fair market value on the vesting 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 $0.6 million for the three months ended March 31, 2014 and 2013. Such expense is recorded in selling, general and administrative expenses. RSUs that may be settled only 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 $2.1 million and $0.5 million to settle liabilities related to cash-settled RSUs in the three months ended March 31, 2014 and 2013. Accrued liabilities for the estimated earned value of outstanding RSUs to be settled in cash were $0.7 million and $2.1 million at March 31, 2014 and December 31, 2013.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	10	COMMITMENTS AND CONTINGENCIES:
	Investments in Affiliates and Other Entities
	As described in Note 8, 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 equally by 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.
	As of March 31, 2014, Quanta had outstanding capital commitments associated with investments in unconsolidated affiliates related to planned midstream infrastructure projects of approximately $13.1 million. Except for approximately $0.5 million that was paid in early April of 2014, Quanta is unable to determine the timing of these capital commitments, but anticipates them to be paid before the end of 2015.
	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 March 31, 2014 (in thousands):
			Operating
			Leases
	Year Ending December 31 —
	Remainder of 2014		$	47,014
	2015			37,193
	2016			29,349
	2017			21,822
	2018			15,250
	Thereafter			25,652
	Total minimum lease payments		$	176,280
	Rent expense related to operating leases was approximately $34.8 million and $24.3 million for the three months ended March 31, 2014 and 2013.
	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 March 31, 2014, the maximum guaranteed residual value was approximately $329.5 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 committed capital for the expansion of its fiber optic network, although Quanta typically does not commit capital to new network expansions until it has a committed licensing arrangement in place with at least one customer. The amounts of committed capital expenditures are estimates of costs required to build the networks under contract. The actual capital expenditures related to building the networks could vary materially from these estimates. As of March 31, 2014, Quanta estimates these committed capital expenditures to be approximately $29.9 million for the period April 1, through December 31, 2014 and $0.4 million for 2015. Quanta also committed capital for the expansion of its vehicle fleet in order to accommodate manufacturer lead times on certain types of vehicles. As of March 31, 2014, production orders for approximately $18.1 million had been issued with delivery dates expected to occur throughout 2014. Although Quanta has committed to purchase these vehicles at the time of their delivery, Quanta intends 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 commitment.
	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.
	National Gas Company of Trinidad and Tobago Arbitration. On October 1, 2010, Mears Group, Inc. (Mears), a wholly-owned subsidiary of Quanta, filed a request for arbitration with the International Chamber of Commerce in London against the National Gas Company of Trinidad and Tobago (NGC). The request for arbitration arose out of a contract between Mears and NGC for directional drilling services in connection with a shore approach of a natural gas pipeline. During pullback of the pipeline, a component on the drill rig operated by Mears failed, and the pipeline was lodged downhole. Subsequent efforts to salvage the pipeline by NGC, Mears and other parties failed to dislodge the pipeline. NGC subsequently hired a separate contractor to complete reworks.
	Mears alleged breach of contract, among other things, and sought recovery for works performed, standby costs, demobilization costs, and other expenses, totaling approximately $16.5 million, including taxes, and additionally sought recovery of pre-judgment interest and attorneys’ fees and expenses. Mears contended in the arbitration that NGC breached the contract between the parties by providing a pipeline with insufficient buoyancy, weighing significantly more than the weight specified in the contract. In addition, Mears argued that NGC failed to provide a contractually required builders all-risk insurance policy naming Mears as an additional insured, which would have covered losses associated with a pullback failure. Moreover, Mears asserted that NGC agreed to indemnify Mears for losses to NGC’s equipment for events occurring during the project, and that any recovery by NGC was therefore barred.
	NGC counterclaimed in the arbitration, asserting that Mears breached the contract and performed negligently by failing to provide a drilling component capable of withstanding loads during pullback and providing a hole of insufficient cleanliness such that debris and other materials contributed to excess forces experienced during Mears’ pullback of the pipeline. NGC sought recovery for the costs of the salvage operations, the cost of the reworks, as well as other costs, totaling approximately $79.5 million, and additionally sought recovery of pre-judgment interest and attorneys’ fees and expenses.
	The arbitration hearings were completed during the third quarter of 2012. On March 20, 2014, the arbitration panel issued a decision in favor of NGC, which awarded $17.3 million in damages plus NGC attorneys’ fees and interest of approximately $11.0 million. As a result, Mears was unsuccessful in recovering any amounts sought in its claim against NGC and has written off approximately $10.5 million of accounts receivable associated with the NGC contract, resulting in an aggregate $38.8 million charge to selling, general and administrative expenses in the three months ended March 31, 2014.
	Sunrise Powerlink Arbitration. On April 21, 2010, PAR, a wholly-owned subsidiary of Quanta, entered into a contract with SDG&E to construct a 117-mile electrical transmission line in Imperial and San Diego Counties, California, known as the Sunrise Powerlink project. Construction commenced on November 17, 2010, with commercial operations beginning on June 17, 2012, according to SDG&E. During the construction phase, SDG&E directed multiple changes to the construction schedule that required PAR to significantly increase its resources to the project in order to meet the customer required completion date. The project also experienced numerous impacts beyond PAR’s control such as access delays and restrictions, as well as problems with customer supplied materials to the project. Following completion of the project, PAR and SDG&E had ongoing meetings to review project scope, costs and performance criteria in order to reach resolution on the additional work performed and pricing of the change order under the contract, which resulted in PAR and SDG&E being in agreement as to PAR’s direct costs incurred in completing the project. Although the parties agreed upon PAR’s direct costs, the parties have been unsuccessful in agreeing on the final amount owed to PAR.
	As a result, PAR initiated arbitration proceedings in the fourth quarter of 2013 pursuant to a contractually agreed upon dispute resolution process. PAR contends that SDG&E breached its obligations under the contract and that, as a result, PAR is entitled to compensation in excess of $165 million plus interest and other relief that PAR may be entitled to under the contract and applicable law. In response, SDG&E disputed that PAR is entitled to the payment of any such additional amounts. On November 18, 2013, SDG&E set forth a counterclaim, which was clarified on January 24, 2014 to seek damages from PAR of approximately $32 million, for PAR’s alleged untimely performance and breach of the contract. Quanta believes that SDG&E’s assertions are without merit and that PAR is entitled to the amount sought in the arbitration process. The parties have initiated discovery and the matter is set for hearing before the arbitration panel in March 2015. Although Quanta believes it is entitled to the amount PAR is seeking, due to the nature of these proceedings, an adverse result in this matter could have a material adverse effect on Quanta’s consolidated financial condition, results of operations and cash flows.
	SEC Notice. On March 10, 2014, the SEC notified Quanta of an inquiry into certain aspects of Quanta’s activities in certain foreign jurisdictions, including South Africa and the United Arab Emirates. The SEC also requested that Quanta take necessary steps to preserve and retain categories of relevant documents, including those pertaining to Quanta’s U.S. Foreign Corrupt Practices Act compliance program. The SEC has not alleged any violations of law by Quanta or its employees. Quanta has complied with the preservation request and is cooperating with the SEC.
	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, oil and gas companies, governmental entities, general contractors, and builders, owners and managers of commercial and industrial properties located primarily in the United States and Canada. Consequently, Quanta is subject to potential credit risk related to changes in business and economic factors throughout the United States and Canada, 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.
	As of March 31, 2014, two customers accounted for approximately 13% and 10% of Quanta’s consolidated net position, which includes accounts receivable including long-term balances and costs and estimated earnings in excess of billings on uncompleted contracts less billings in excess of costs and unearned revenue. As of December 31, 2013, the same two customers accounted for approximately 15% and 11% of Quanta’s consolidated net position. The services provided to these customers relate primarily to Quanta’s Electric Power Infrastructure Services segment. Substantially all of the balance for the customer with 10% of consolidated net position as of March 31, 2014 and 11% at December 31, 2013 relates to the Sunrise Powerlink project with a long-term receivable balance related to a significant change order that is subject to a contractually agreed upon arbitration process. For additional information, see Legal Proceedings - Sunrise Powerlink Arbitration within this Note 10. Additionally, the customer with the 13% and 15% of consolidated net position at March 31, 2014 and December 31, 2013 also accounted for 14% of consolidated revenues for the three months ended March 31, 2013. No other customers represented 10% or more of revenues for the three months ended March 31, 2014 and 2013, and no other customers represented 10% or more of consolidated net position as of March 31, 2014 and December 31, 2013.
	Self-Insurance
	Quanta is insured for employer’s liability, general liability, auto liability and workers’ compensation claims. On August 1, 2013, Quanta renewed its employer’s liability, general liability, auto liability and workers’ compensation policies for the 2013 — 2014 policy year. As a result of the renewal, the deductibles for general liability and auto liability increased from $5.0 million to $10.0 million per occurrence, while the deductible for workers’ compensation remained at $5.0 million per occurrence and the deductible for employer’s liability remained at $1.0 million per occurrence. Additionally, in connection with this renewal, the amount of letters of credit required by Quanta to secure its obligations under its casualty insurance programs, which is discussed further below, has increased. 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. As of March 31, 2014 and December 31, 2013, the gross amount accrued for insurance claims totaled $163.1 million and $161.8 million, with $122.0 million and $122.6 million considered to be long-term and included in other non-current liabilities. Related insurance recoveries/receivables as of March 31, 2014 and December 31, 2013 were $9.3 million and $9.1 million, of which $0.7 million and $0.7 million were included in prepaid expenses and other current assets and $8.6 million and $8.4 million were included in other assets, net.
	Quanta renews its insurance policies on an annual basis, and therefore deductibles and levels of insurance coverage may change in future periods. In addition, insurers may cancel Quanta’s coverage or determine to exclude certain items from coverage, or Quanta may elect not to obtain certain types or incremental levels of insurance if it believes that the cost to obtain such coverage exceeds the additional benefits obtained. In any such event, Quanta’s overall risk exposure would increase, which could negatively affect its results of operations, financial condition and cash flows.
	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 March 31, 2014, Quanta had $213.5 million in letters of credit outstanding under its credit facility primarily to secure obligations under its casualty insurance program. These are irrevocable stand-by letters of credit with maturities generally expiring at various times throughout 2014 and 2015. Upon maturity, it is expected that the majority of these letters of credit 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. As of March 31, 2014, the total amount of outstanding performance bonds was approximately $2.50 billion, and the estimated cost to complete these bonded projects was approximately $717.2 million.
	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.
	In the fourth quarter of 2011, Quanta recorded a partial withdrawal liability of approximately $32.6 million related to the withdrawal by certain Quanta subsidiaries from the Central States, Southeast and Southwest Areas Pension Plan (the Central States Plan). The partial withdrawal liability recognized by Quanta was based on estimates received from the Central States Plan during 2011 for a complete withdrawal by all Quanta companies participating in the Central States Plan. The withdrawal followed an amendment to a collective bargaining agreement with the International Brotherhood of Teamsters that eliminated obligations to contribute to the Central States Plan, which is in critical status and is significantly underfunded as to its vested benefit obligations. The amendment was negotiated by the Pipe Line Contractors Association (PLCA) on behalf of its members, which include the Quanta subsidiaries that withdrew from the Central States Plan. Quanta believed that withdrawing from the Central States Plan in the fourth quarter of 2011 was advantageous because it limited Quanta’s exposure to increased liabilities from a future withdrawal if the underfunded status of the Central States Plan deteriorates further. Quanta and other PLCA members now contribute to a different multi-employer pension plan on behalf of Teamsters employees.
	The Central States Plan asserted that the withdrawal of the PLCA members was not effective in 2011, although Quanta believed at that time that a legally effective withdrawal had occurred during the fourth quarter of 2011. Certain other Quanta subsidiaries continued participation in the Central States Plan, and Quanta believes that it subsequently effected a complete withdrawal as of December 30, 2012. Although the federal district court for the Northern District of Illinois, Eastern Division, ruled that the withdrawal of the PLCA members was not effective in 2011, the PLCA appealed the decision, and the outcome of that appeal remains uncertain.
	In December 2013, the Central States Plan filed a lawsuit against certain of Quanta’s subsidiaries alleging that contributions made to a new industry fund created after Quanta withdrew from the Central States Plan should have been made to the Central States Plan, which arguably would extend the date of withdrawal for those subsidiaries to 2014. Quanta has disputed these allegations on the basis that it has properly paid contributions to the new industry fund based on the terms of the collective bargaining agreements under which its subsidiaries participate.
	On March 26, 2014, a Quanta subsidiary was notified of a Joint Committee decision relating to a grievance matter concluding that the Quanta subsidiary should have hired Teamsters under a specific collective bargaining agreement to perform certain jobs. Quanta disputes this decision and is weighing its appeal options. However, if the decision stands, there is an argument that the Quanta subsidiary owes back wages and benefits, including pension contributions, to two Teamsters employees as set forth in that collective bargaining agreement for work performed in 2013. The Central States Plan may argue that such pension contributions would be due to them from the Quanta subsidiary, which arguably would extend the date on which Quanta effected complete withdrawal from the Central States Plan to 2013. In addition, in March 2014, the Central States Plan provided revised estimates indicating that the withdrawal liability based on certain withdrawal scenarios from 2011 through 2014 could range between $40.1 million and $55.4 million.
	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 has 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 a revised range of estimated probable liability associated with the Central States Plan. Given the unknown nature of some of these factors, the final withdrawal liability cannot yet be determined with certainty; therefore the amount ultimately owed upon final settlement of these matters could be materially higher than the liability Quanta has recognized through March 31, 2014.
	On October 9, 2013, Quanta acquired a company that experienced a complete withdrawal from the Central States Plan prior to the date of acquisition. The Central States Plan issued a notice and demand, dated March 13, 2013, to the acquired company for a withdrawal liability in the total amount of $6.9 million payable in installments. Based on legal arguments, the acquired company took the position that the amount of withdrawal liability payable to the Central States Plan as a result of its complete withdrawal was $4.8 million, of which approximately $4.1 million was outstanding as of March 31, 2014. The acquired company and Quanta have taken steps to challenge the amount of the assessment by the Central States Plan; however, payments in accordance with the terms of the Central States Plan’s demand letter are required to be made while the dispute is ongoing. Approximately $2.1 million of the purchase price was deposited into an escrow account on October 9, 2013 to fund any withdrawal obligation in excess of the $4.8 million initially demanded. Accordingly, the acquired company’s withdrawal from the Central States Plan is not expected to have a material impact on Quanta’s results of operations, financial condition or cash flows.
	Indemnities
	Quanta generally indemnifies its customers for the services it provides under its contracts, as well as other specified liabilities, which may subject Quanta to indemnity claims and liabilities and related litigation. Quanta has also indemnified various parties against specified liabilities that those parties might incur in the future in connection with Quanta’s previous acquisition or disposition of certain companies. The indemnities under acquisition or disposition agreements are usually contingent upon the other party incurring liabilities that reach specified thresholds. As of March 31, 2014, except as otherwise set forth above in Legal Proceedings, Quanta does not believe any material liabilities for asserted claims exist against it in connection with any of these indemnity obligations.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	11	SEGMENT INFORMATION:
	Quanta presents its operations under three reportable segments: (1) Electric Power Infrastructure Services, (2) Oil and Gas Infrastructure Services and (3) Fiber Optic Licensing and Other. 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 three internal divisions, namely, the electric power division, oil and gas infrastructure division and fiber optic licensing 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, including allocations of shared and indirect costs, such as facility costs, 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
			March 31,
			2014			2013
	Revenues:
	Electric Power		$	1,278,168		$	1,180,983
	Oil and Gas Infrastructure			445,857			358,932
	Fiber Optic Licensing and Other			38,549			45,795
	Consolidated		$	1,762,574		$	1,585,710
	Operating income (loss):
	Electric Power		$	144,412		$	132,550
	Oil and Gas Infrastructure			(21,172	)		10,357
	Fiber Optic Licensing and Other			12,109			16,883
	Corporate and non-allocated costs			(44,854	)		(40,499	)
	Consolidated		$	90,495		$	119,291
	Depreciation:
	Electric Power		$	17,564		$	14,923
	Oil and Gas Infrastructure			13,215			11,265
	Fiber Optic Licensing and Other			4,318			4,051
	Corporate and non-allocated costs			1,768			1,641
	Consolidated		$	36,865		$	31,880
	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, 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 March 31, 2014 and 2013, Quanta derived $456.2 million and $299.2 million of its revenues from foreign operations. Of Quanta’s foreign revenues, approximately 84% and 96% was earned in Canada during the three months ended March 31, 2014 and 2013. In addition, Quanta held property and equipment of $226.1 million and $196.8 million in foreign countries, primarily Canada, as of March 31, 2014 and December 31, 2013. The increases in foreign revenues and assets were primarily due to the timing of the non-U.S. acquisitions described in Note 4.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	12	SUBSEQUENT EVENTS:
	Acquisition
	During the second quarter of 2014, Quanta completed the acquisition of a company that offers geotechnical and geological engineering services for the power transmission, mining, transportation, and water resources sectors in the U.S., Canada and select international markets. The consideration paid for this acquisition consisted of approximately $3.3 million in cash and will include shares of Quanta common stock valued at approximately $2.0 million as of the final determination date, which will be at the end of May 2014. As this transaction was effective during the second quarter of 2014, 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 the U.S., Canada and select international markets.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
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 20% to 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 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, 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, 2013, which was filed with the SEC on March 3, 2014.
Use of Estimates and Assumptions	'
	Use of Estimates and Assumptions
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States 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 amount 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, multi-employer pension plan withdrawal liabilities, revenue recognition for construction contracts and fiber optic licensing, share-based compensation, operating results of reportable segments, as well as the provision for income taxes and the calculation of uncertain tax positions.
Reclassifications	'
	Reclassifications
	Certain reclassifications have been made to prior year’s balance sheet to conform to classifications used in the current year.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	Quanta had cash and cash equivalents of $273.3 million and $488.8 million as of March 31, 2014 and December 31, 2013. Cash consisting of interest-bearing demand deposits is carried at cost, which approximates fair value. Quanta considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents, which are carried at fair value. At March 31, 2014 and December 31, 2013, cash equivalents were $66.5 million and $247.8 million, which consisted primarily of money market mutual funds and are discussed further in “Fair Value Measurements” below. As of March 31, 2014 and December 31, 2013, cash and cash equivalents held in domestic bank accounts were approximately $134.1 million and $236.7 million, and cash and cash equivalents held in foreign bank accounts were approximately $139.2 million and $252.1 million.
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 including, among others, the customer’s access to capital, the customer’s willingness or ability to pay, general economic and market conditions and the ongoing relationship with the customer. 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 March 31, 2014 and December 31, 2013, Quanta had total allowances for doubtful accounts of approximately $5.2 million, all of which were included as a reduction of net current accounts receivable. 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 March 31, 2014 and December 31, 2013 were approximately $194.6 million and $194.5 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 March 31, 2014 and December 31, 2013 were $55.6 million and $50.8 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 March 31, 2014 and December 31, 2013, the balances of unbilled receivables included in accounts receivable were approximately $211.9 million and $179.2 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 have been 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 three internal divisions: the Electric Power Division, the Oil and Gas Infrastructure Division or the Fiber Optic Licensing 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 operating segment level or one level below the operating segment level for which discrete financial information is available, and 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 performing 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 2013, 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 2013 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, 2013 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.
	Quanta’s intangible assets include customer relationships, backlog, trade names, non-compete agreements, patented rights and developed technology, all subject to amortization, along with other intangible assets not 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, 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 finance 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 noncontrolling 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 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
	Infrastructure Services — 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 three months ended March 31, 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, 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 March 31, 2014 and December 31, 2013, Quanta had approximately $247.2 million and $241.8 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. The March 31, 2014 and December 31, 2013 balances of recognized change orders and claims included a change order from the Sunrise Powerlink project, an electric power infrastructure services project, primarily as a result of multiple customer-directed changes to the construction schedule which required PAR Electrical Contractors, Inc. (PAR), a wholly-owned subsidiary of Quanta, to significantly increase its resources to the project in order to meet the customer required completion date. Revenues of approximately $165 million associated with this change order were accrued and recognized as a component of costs and estimated earnings in excess of billings on uncompleted contracts in prior years. Following completion of the project, PAR and its customer, San Diego Gas & Electric Company (SDG&E), had ongoing meetings to review project scope, costs and performance criteria in order to reach resolution on the additional work performed and pricing of the change order under the contract, which resulted in PAR and SDG&E being in agreement as to PAR’s direct costs incurred in completing the project. Although the parties agreed upon PAR’s direct costs, the parties have been unsuccessful in agreeing on the final amount owed to PAR. As a result, PAR initiated arbitration proceedings in the fourth quarter of 2013 pursuant to a contractually agreed upon dispute resolution process. See Legal Proceedings - Sunrise Powerlink Arbitration in Note 10 for additional information. Quanta reclassified the recognized balance related to this contract from costs and estimated earnings in excess of billings on uncompleted contracts into other assets, net as this process is not expected to conclude within the next twelve months. As of March 31, 2014, no interest has been accrued related to this long-term receivable since the arbitration process is still ongoing. The aggregate contract price adjustments discussed above 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. Although Quanta believes that it is entitled to the amount PAR is seeking in the matter related to the Sunrise Powerlink project, due to the nature of those proceedings, an adverse result in that matter could have a material adverse effect on Quanta’s consolidated financial condition, results of operations and cash flows.
	Fiber Optic Licensing — The fiber optic licensing business constructs and licenses the right to use fiber optic telecommunications facilities to its customers pursuant to licensing agreements, typically with terms from five to twenty-five years, inclusive of certain renewal options. Under those agreements, customers are provided the right to use a portion of the capacity of a fiber optic facility, with the facility owned and maintained by Quanta. Revenues, including any initial fees or advance billings, are recognized ratably over the expected length of the agreements, including probable renewal periods. As of March 31, 2014 and December 31, 2013, initial fees and advance billings on these licensing agreements not yet recorded in revenue were $49.7 million and $48.8 million and are recognized as deferred revenue, with $41.6 million and $40.2 million considered to be long-term and included in other non-current liabilities. Minimum future licensing revenues expected to be recognized by Quanta pursuant to these agreements at March 31, 2014 were as follows (in thousands):
		Minimum Future
		Licensing
		Revenues
	Year Ending December 31 —
	Remainder of 2014	$	61,418
	2015		57,394
	2016		47,581
	2017		38,096
	2018		28,080
	Thereafter		133,227
	Fixed non-cancelable minimum licensing revenues	$	365,796
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 March 31, 2014, the total amount of unrecognized tax benefits relating to uncertain tax positions was $51.2 million, an increase from December 31, 2013 of $2.4 million. This increase in unrecognized tax benefits is primarily due to tax positions expected to be taken for 2014. Certain subsidiaries are under examination by various U.S. state and Canadian federal tax authorities for multiple periods. Quanta believes that it is reasonably possible that within the next 12 months unrecognized tax benefits may decrease up to $11.0 million as a result of settlement of these audits 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.
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 any 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 and restricted stock units (RSUs) to be settled in common stock based on the fair value of the awards granted, net of estimated forfeitures, at the date of grant. The fair value of restricted stock awards and RSUs to be settled in common stock is determined based on the number of shares or RSUs 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. Restricted stock awards and RSUs to be settled in common stock are subject to forfeiture, restrictions on transfer and certain other conditions until vesting. During the restriction period, holders of restricted stock are entitled to vote and receive dividends on such shares. The cash flows resulting from the tax deductions in excess of the compensation expense recognized for restricted stock, RSUs 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 be settled in cash, is recognized based on a remeasurement of the fair value of the award at the end of each reporting period. RSUs to be settled in cash are intended to provide the holders with cash performance incentives that are substantially equivalent to the risks and rewards of equity ownership in Quanta. RSUs to be settled in cash 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. Upon vesting of RSUs to be settled in cash, the holders receive for each vested RSU an amount in cash equal to the fair market value on the vesting date of one share of Quanta common stock, as specified in the applicable award agreement.
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. Under the relevant accounting guidance, 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 (loss) and cash flows are translated at average monthly rates, while balance sheets are translated at the month-end exchange rates. The translation of the balance sheets at the month-end exchange rates results in translation gains or losses. If transactions are denominated in the operating units’ functional currency, the translation gains and losses are included as a separate component of equity under the caption “Accumulated other comprehensive income (loss).” If transactions are not denominated in the operating units’ functional currency, the translation gains and losses are included within the statement 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), net of tax, 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 10.
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. 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 March 31, 2014 and December 31, 2013, 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. The level of inputs used for these fair value measurements is the lowest level (Level 3). Quanta believes that these valuation methods appropriately represent the methods that would be used by other market participants in determining fair value.
	Quanta uses fair value measurements on a routine basis in its assessment of assets classified as goodwill, other intangible assets and long-lived assets held and used. In accordance with its annual impairment test during the quarter ended December 31, 2013, the carrying amounts of such assets, including goodwill, were compared to their fair values. The inputs used for fair value measurements for goodwill, other intangible assets and long-lived assets held and used are the lowest level (Level 3) inputs, and Quanta uses the assistance of third party specialists to develop valuation assumptions.
	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.
New Accounting Pronouncements	'
	Adoption of New Accounting Pronouncements
	On January 1, 2014, Quanta adopted an update that provides guidance on the balance sheet presentation of an unrecognized tax benefit when a net operating loss carryforward, similar tax loss, or tax credit carryforward exists as of the reporting date. The update is effective prospectively for fiscal years, and interim periods within those years, beginning after December 15, 2013. The impact of the adoption of this standard did not have a material effect on Quanta’s consolidated financial statements.
Accounting Standards Not Yet Adopted	'
	Accounting Standards Not Yet Adopted
	In April of 2014, the 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. The update is effective prospectively for fiscal years beginning on or after December 15, 2014 and interim periods within those years. Early adoption is permitted, but only for disposals (or classifications as held for sale) that have not been reported in previously issued financial statements. 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, 2015.
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, up to $500.0 million of its outstanding common stock through December 31, 2016. As of March 31, 2014, there had been no repurchases under this plan. The shares and the related cost to acquire them will be accounted for as an adjustment to the balance of treasury stock.
Segment Reporting	'
	Quanta presents its operations under three reportable segments: (1) Electric Power Infrastructure Services, (2) Oil and Gas Infrastructure Services and (3) Fiber Optic Licensing and Other. 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 three internal divisions, namely, the electric power division, oil and gas infrastructure division and fiber optic licensing 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, including allocations of shared and indirect costs, such as facility costs, 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, 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.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Minimum Future Licensing Revenue	'
	Minimum future licensing revenues expected to be recognized by Quanta pursuant to these agreements at March 31, 2014 were as follows (in thousands):
		Minimum Future
		Licensing
		Revenues
	Year Ending December 31 —
	Remainder of 2014	$	61,418
	2015		57,394
	2016		47,581
	2017		38,096
	2018		28,080
	Thereafter		133,227
	Fixed non-cancelable minimum licensing revenues	$	365,796

Acquisitions_Tables

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2014
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).
	Consideration:
	Value of Quanta common stock and exchangeable shares issued	$	36,604		$	88,895
	Cash paid		79,927			341,064
	Fair value of total consideration transferred	$	116,531		$	429,959
	Current assets	$	52,986		$	193,895
	Property and equipment		33,387			60,988
	Other assets		3,373			1,009
	Identifiable intangible assets		21,048			55,124
	Current liabilities		(41,281	)		(127,430	)
	Deferred tax liabilities, net		(3,692	)		(4,083	)
	Other long-term liabilities		(3,935	)		(5,350	)
	Total identifiable net assets		61,886			174,153
	Goodwill		54,645			255,806
		$	116,531		$	429,959
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
		March 31,
		2014			2013
	Revenues	$	1,766,756		$	1,785,809
	Gross profit	$	271,736		$	277,641
	Selling, general and administrative expenses	$	174,359		$	128,020
	Amortization of intangible assets	$	8,326		$	9,236
	Net income	$	57,675		$	89,915
	Net income attributable to common stock	$	53,435		$	85,139
	Earnings per share attributable to common stock - basic and diluted	$	0.24		$	0.39

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2014
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			Oil and Gas			Fiber Optic			Total
		Division			Infrastructure			Licensing
					Division			Division
	Goodwill balance at December 31, 2013	$	1,168,084		$	277,843		$	334,790		$	1,780,717
	Goodwill acquired during 2014		47,089			7,556			—			54,645
	Foreign currency translation related to goodwill		(5,261	)		1,946			—			(3,315	)
	Goodwill balance at March 31, 2014	$	1,209,912		$	287,345		$	334,790		$	1,832,047
Other Intangible Assets	'
	Activity in Quanta’s intangible assets consisted of the following (in thousands):
		As of						Three Months Ended									As of
		December 31, 2013						March 31, 2014									March 31, 2014
		Intangible			Accumulated			Amortization			Additions			Foreign			Intangible		Remaining
		Assets			Amortization			Expense						Currency			Assets, Net		Weighted
														Adjustments					Average
																			Amortization
																			Period in Years
	Customer relationships	$	199,224		$	(59,417	)	$	(3,650	)	$	11,131		$	195		$	147,483		10.6
	Backlog		136,831			(127,233	)		(2,957	)		4,908			730			12,279		0.9
	Trade names		40,342			(4,228	)		(466	)		3,917			(1,954	)		37,611		22.7
	Non-compete agreements		28,895			(22,861	)		(652	)		688			(71	)		5,999		3.3
	Patented rights and developed technology		21,440			(9,616	)		(520	)		404			(7	)		11,701		5.1
	Total intangible assets subject to amortization		426,732			(223,355	)		(8,245	)		21,048			(1,107	)		215,073		11.6
	Other intangible assets not subject to amortization		4,500			—			—			—			—			4,500		N/A
	Total intangible assets	$	431,232		$	(223,355	)	$	(8,245	)	$	21,048		$	(1,107	)	$	219,573		N/A
Estimated Future Aggregate Amortization Expense of Intangible Assets	'
	The estimated future aggregate amortization expense of intangible assets as of March 31, 2014 is set forth below (in thousands):
	For the Fiscal Year Ending December 31,
	Remainder of 2014	$	25,088
	2015		21,875
	2016		20,503
	2017		19,043
	2018		18,776
	Thereafter		109,788
	Total	$	215,073

Per_Share_Information_Tables

Per Share Information (Tables)	3 Months Ended
	Mar. 31, 2014
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 months ended March 31, 2014 and 2013 are illustrated below (in thousands):
		Three Months Ended
		March 31,
		2014		2013
	AMOUNTS ATTRIBUTABLE TO COMMON STOCK:
	Net income attributable to common stock	$	54,408	$	72,081
	WEIGHTED AVERAGE SHARES:
	Weighted average shares outstanding for basic earnings per share		219,033		213,453
	Effect of dilutive stock options		42		59
	Weighted average shares outstanding for diluted earnings per share		219,075		213,512

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Minimum Lease Payments	'
	The following schedule shows the future minimum lease payments under these leases as of March 31, 2014 (in thousands):
		Operating
		Leases
	Year Ending December 31 —
	Remainder of 2014	$	47,014
	2015		37,193
	2016		29,349
	2017		21,822
	2018		15,250
	Thereafter		25,652
	Total minimum lease payments	$	176,280

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
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
		March 31,
		2014			2013
	Revenues:
	Electric Power	$	1,278,168		$	1,180,983
	Oil and Gas Infrastructure		445,857			358,932
	Fiber Optic Licensing and Other		38,549			45,795
	Consolidated	$	1,762,574		$	1,585,710
	Operating income (loss):
	Electric Power	$	144,412		$	132,550
	Oil and Gas Infrastructure		(21,172	)		10,357
	Fiber Optic Licensing and Other		12,109			16,883
	Corporate and non-allocated costs		(44,854	)		(40,499	)
	Consolidated	$	90,495		$	119,291
	Depreciation:
	Electric Power	$	17,564		$	14,923
	Oil and Gas Infrastructure		13,215			11,265
	Fiber Optic Licensing and Other		4,318			4,051
	Corporate and non-allocated costs		1,768			1,641
	Consolidated	$	36,865		$	31,880

Business_and_Organization_Addi

Business and Organization - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	Entity		Entity
	Segment
Organization And Description Of Business [Line Items]	'	'	'
Number of reportable segments	3	'	'
Fiber Optic Licensing Terms, Minimum in years	'5 years	'5 years	'5 years
Fiber Optic Licensing Terms, Maximum in years	'25 years	'25 years	'25 years
Number of business acquisitions	5	'	6
Electric Power Infrastructure Services Business [Member] | Canada [Member]	'	'	'
Organization And Description Of Business [Line Items]	'	'	'
Number of business acquisitions	4	'	'
Oil and Gas Infrastructure Services Business [Member] | United States [Member]	'	'	'
Organization And Description Of Business [Line Items]	'	'	'
Number of business acquisitions	1	'	'

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended			12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Cash and cash equivalents	$273,340,000	$488,777,000	$366,619,000	$488,777,000	$394,701,000
Cash equivalents	66,500,000	247,800,000	'	247,800,000	'
Cash and cash equivalents held in domestic bank accounts	134,100,000	236,700,000	'	236,700,000	'
Cash and cash equivalents held in foreign bank accounts	139,200,000	252,100,000	'	252,100,000	'
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	'At least 90 days	'	'	'
Total allowances for doubtful accounts	5,186,000	5,215,000	'	5,215,000	'
Current retainage balances	194,600,000	194,500,000	'	194,500,000	'
Non-current retainage balances	55,600,000	50,800,000	'	50,800,000	'
Unbilled receivables	211,900,000	179,200,000	'	179,200,000	'
Decrease in fair value of reporting units considered, for impairment calculation	'	10.00%	'	10.00%	'
Percent change in contract estimates impact on operating results is less than this percentage	5.00%	'	'	'	'
Change orders and/or claims	247,200,000	241,800,000	'	241,800,000	'
Fiber Optic Licensing Terms, Minimum in years	'5 years	'	'5 years	'5 years	'
Fiber Optic Licensing Terms, Maximum in years	'25 years	'	'25 years	'25 years	'
Fiber optic deferred revenue	49,700,000	48,800,000	'	48,800,000	'
Fiber optic non-current deferred revenue	41,600,000	40,200,000	'	40,200,000	'
Total amount of unrecognized tax benefits relating to uncertain tax positions	51,200,000	'	'	'	'
Amount of unrecognized tax benefits change from year-end relating to uncertain tax positions	2,400,000	'	'	'	'
Reasonably possible reduction to the balance of unrecognized tax benefits in succeeding 12 months upper bound	11,000,000	'	'	'	'
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	'	'	'	'
Sunrise Powerlink Project [Member]	'	'	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Revenue associated with change order	$165,000,000	'	'	'	'
Minimum [Member]	'	'	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Equity Method Investment ownership	20.00%	'	'	'	'
Minimum [Member] | Restricted Stock Units to be Settled in Cash [Member]	'	'	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Vesting period for restricted stock units to be settled in cash	'2 years	'	'	'	'
Maximum [Member]	'	'	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Equity Method Investment ownership	50.00%	'	'	'	'
Maximum [Member] | Restricted Stock Units to be Settled in Cash [Member]	'	'	'	'	'
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'
Vesting period for restricted stock units to be settled in cash	'3 years	'	'	'	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Minimum Future Licensing Revenues (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Accounting Policies [Abstract]	'
Remainder of 2014	$61,418
2015	57,394
2016	47,581
2017	38,096
2018	28,080
Thereafter	133,227
Fixed non-cancelable minimum licensing revenues	$365,796

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
	Entity	Entity
Business Acquisition [Line Items]	'	'
Number of business acquisitions	5	6
Cash paid for acquisitions	$79,900,000	$341,100,000
Number of shares granted for acquired company	393,052	3,547,482
Common stock value	36,604,000	88,895,000
Fair value of accounts receivable acquired	31,100,000	83,900,000
Goodwill acquired	54,645,000	'
Revenues contributed by acquisitions	37,000,000	'
Acquisition costs	4,200,000	'
Income (loss) before income taxes contributed by acquisitions	-100,000	'
Electric Power Infrastructure Services Business [Member] | Canada [Member]	'	'
Business Acquisition [Line Items]	'	'
Number of business acquisitions	4	'
Oil and Gas Infrastructure Services Business [Member] | United States [Member]	'	'
Business Acquisition [Line Items]	'	'
Number of business acquisitions	1	'
Acquisitions [Member]	'	'
Business Acquisition [Line Items]	'	'
Goodwill expected to be deductible for income tax	7,600,000	213,600,000
Electric Power Division [Member]	'	'
Business Acquisition [Line Items]	'	'
Goodwill acquired	47,089,000	'
Electric Power Division [Member] | Acquisitions [Member]	'	'
Business Acquisition [Line Items]	'	'
Goodwill acquired	47,000,000	112,500,000
Oil and Gas Infrastructure Division [Member]	'	'
Business Acquisition [Line Items]	'	'
Goodwill acquired	7,556,000	'
Oil and Gas Infrastructure Division [Member] | Acquisitions [Member]	'	'
Business Acquisition [Line Items]	'	'
Goodwill acquired	$7,600,000	$143,300,000
Exchangeable Shares [Member] | Canadian Subsidiaries [Member]	'	'
Business Acquisition [Line Items]	'	'
Number of shares granted for acquired company	899,858	'
Series G Preferred Stock [Member]	'	'
Business Acquisition [Line Items]	'	'
Number of shares granted for acquired company	1	'

Acquisition_Business_Acquisiti

Acquisition - Business Acquisition Purchase Price Allocation Assets Acquired and Liabilities Assumed (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]	'	'
Value of Quanta common stock and exchangeable shares issued	$36,604	$88,895
Cash paid	79,900	341,100
All Acquisitions [Member]	'	'
Business Acquisition [Line Items]	'	'
Cash paid	79,927	341,064
Fair value of total consideration transferred	116,531	429,959
Current assets	52,986	193,895
Property and equipment	33,387	60,988
Other assets	3,373	1,009
Identifiable intangible assets	21,048	55,124
Current liabilities	-41,281	-127,430
Deferred tax liabilities, net	-3,692	-4,083
Other long-term liabilities	-3,935	-5,350
Total identifiable net assets	61,886	174,153
Goodwill	54,645	255,806
Fair value of total consideration transferred	$116,531	$429,959

Acquisitions_Unaudited_Supplem

Acquisitions - Unaudited Supplemental Proforma Results of Operations (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Business Combinations [Abstract]	'	'
Revenues	$1,766,756	$1,785,809
Gross profit	271,736	277,641
Selling, general and administrative expenses	174,359	128,020
Amortization of intangible assets	8,326	9,236
Net income	57,675	89,915
Net income attributable to common stock	$53,435	$85,139
Earnings per share attributable to common stock - basic and diluted	$0.24	$0.39

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Summary of Changes in Quanta's Goodwill (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014
Goodwill [Line Items]	'
Goodwill, beginning balance	$1,780,717
Goodwill acquired	54,645
Foreign currency translation related to goodwill	-3,315
Goodwill, ending balance	1,832,047
Electric Power Division [Member]	'
Goodwill [Line Items]	'
Goodwill, beginning balance	1,168,084
Goodwill acquired	47,089
Foreign currency translation related to goodwill	-5,261
Goodwill, ending balance	1,209,912
Oil and Gas Infrastructure Division [Member]	'
Goodwill [Line Items]	'
Goodwill, beginning balance	277,843
Goodwill acquired	7,556
Foreign currency translation related to goodwill	1,946
Goodwill, ending balance	287,345
Fiber Optic Licensing Division[Member]	'
Goodwill [Line Items]	'
Goodwill, beginning balance	334,790
Goodwill acquired	'
Foreign currency translation related to goodwill	'
Goodwill, ending balance	$334,790

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Other Intangible Assets (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Finite And Indefinite Lived Intangible Assets [Line Items]	'	'	'
Intangible assets subject to amortization	'	'	$426,732
Indefinite-lived Intangible Assets	4,500	'	4,500
Intangible assets, gross	'	'	431,232
Accumulated Amortization	-230,712	'	-223,355
Amortization Expense	-8,245	-5,301	'
Additions	21,048	'	'
Foreign Currency Adjustments	-1,107	'	'
Intangible Assets Subject to Amortization, Net	215,073	'	'
Intangible assets, net	219,573	'	207,877
Remaining Weighted Average Amortization Period in Years	'11 years 7 months 6 days	'	'
Customer Relationships [Member]	'	'	'
Finite And Indefinite Lived Intangible Assets [Line Items]	'	'	'
Intangible assets subject to amortization	'	'	199,224
Accumulated Amortization	'	'	-59,417
Amortization Expense	-3,650	'	'
Additions	11,131	'	'
Foreign Currency Adjustments	195	'	'
Intangible Assets Subject to Amortization, Net	147,483	'	'
Remaining Weighted Average Amortization Period in Years	'10 years 7 months 6 days	'	'
Backlog [Member]	'	'	'
Finite And Indefinite Lived Intangible Assets [Line Items]	'	'	'
Intangible assets subject to amortization	'	'	136,831
Accumulated Amortization	'	'	-127,233
Amortization Expense	-2,957	'	'
Additions	4,908	'	'
Foreign Currency Adjustments	730	'	'
Intangible Assets Subject to Amortization, Net	12,279	'	'
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	'	'	40,342
Accumulated Amortization	'	'	-4,228
Amortization Expense	-466	'	'
Additions	3,917	'	'
Foreign Currency Adjustments	-1,954	'	'
Intangible Assets Subject to Amortization, Net	37,611	'	'
Remaining Weighted Average Amortization Period in Years	'22 years 8 months 12 days	'	'
Non-compete Agreements [Member]	'	'	'
Finite And Indefinite Lived Intangible Assets [Line Items]	'	'	'
Intangible assets subject to amortization	'	'	28,895
Accumulated Amortization	'	'	-22,861
Amortization Expense	-652	'	'
Additions	688	'	'
Foreign Currency Adjustments	-71	'	'
Intangible Assets Subject to Amortization, Net	5,999	'	'
Remaining Weighted Average Amortization Period in Years	'3 years 3 months 18 days	'	'
Patented Rights and Developed Technology [Member]	'	'	'
Finite And Indefinite Lived Intangible Assets [Line Items]	'	'	'
Intangible assets subject to amortization	'	'	21,440
Accumulated Amortization	'	'	-9,616
Amortization Expense	-520	'	'
Additions	404	'	'
Foreign Currency Adjustments	-7	'	'
Intangible Assets Subject to Amortization, Net	$11,701	'	'
Remaining Weighted Average Amortization Period in Years	'5 years 1 month 6 days	'	'

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'	'
Amortization of intangible assets	$8,245	$5,301

Goodwill_and_Other_Intangible_5

Goodwill and Other Intangible Assets - Estimated Future Aggregate Amortization Expense of Intangible Assets (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Goodwill And Intangible Assets Disclosure [Abstract]	'
Remainder of 2014	$25,088
2015	21,875
2016	20,503
2017	19,043
2018	18,776
Thereafter	109,788
Total	$215,073

Per_Share_Information_Basic_an

Per Share Information - Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
AMOUNTS ATTRIBUTABLE TO COMMON STOCK:	'	'
Net income attributable to common stock	$54,408	$72,081
WEIGHTED AVERAGE SHARES:	'	'
Weighted average shares outstanding for basic earnings per share	219,033	213,453
Effect of dilutive stock options	42	59
Weighted average shares outstanding for diluted earnings per share	219,075	213,512

Debt_Obligations_Additional_In

Debt Obligations - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Line of Credit Facility [Line Items]	'
Letters of credit issued under the credit facility	$213,500,000
Amount borrowed under the credit facility	0
Credit facility available for revolving loans or issuing new letters of credit	1,110,000,000
U S Dollar [Member]	'
Line of Credit Facility [Line Items]	'
Letters of credit issued under the credit facility	186,700,000
Canada And Australia Dollar [Member]	'
Line of Credit Facility [Line Items]	'
Letters of credit issued under the credit facility	26,800,000
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
Base rate in excess of Federal Funds Rate	0.50%
One possible rate is this rate in excess of Eurocurrency Rate	1.00%
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
First Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Senior secured revolving credit facility	700,000,000
Maturity date of senior secured revolving credit facility	2-Aug-16
Reduction in Quanta's maximum funded debt and maximum senior debt by all cash and cash equivalents in excess of amount	25,000,000
Base rate in excess of Federal Funds Rate	0.50%
One possible rate is this rate in excess of Eurocurrency Rate	1.00%
Minimum [Member] | First Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Commitment fee	0.20%
Letter of credit fee	1.25%
Interest rate in excess of Eurocurrency rate applicable to domestic borrowings only	1.25%
Interest rate in excess of base rate, domestic borrowings only	0.25%
Interest rate in excess of Eurocurrency rate of credit agreement for foreign borrowings	1.25%
Maximum [Member] | First Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Commitment fee	0.45%
Letter of credit fee	2.50%
Interest rate in excess of Eurocurrency rate applicable to domestic borrowings only	2.50%
Interest rate in excess of base rate, domestic borrowings only	1.50%
Interest rate in excess of Eurocurrency rate of credit agreement for foreign borrowings	2.50%
Prior to April 1, 2014 [Member] | Second Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Commitment fee	0.20%
Letter of credit fee	1.25%
Interest rate in excess of Eurocurrency rate applicable to domestic borrowings only	1.25%
Interest rate in excess of base rate, domestic borrowings only	0.25%
Interest rate in excess of Eurocurrency rate of credit agreement for foreign borrowings	1.25%
Prior to April 1, 2014 [Member] | Performance Letters Of Credit [Member] | Second Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Letter of credit fee	0.75%
Effective April 1, 2014 [Member] | Minimum [Member] | Second Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Commitment fee	0.20%
Letter of credit fee	1.13%
Interest rate in excess of Eurocurrency rate applicable to domestic borrowings only	1.13%
Interest rate in excess of base rate, domestic borrowings only	0.13%
Interest rate in excess of Eurocurrency rate of credit agreement for foreign borrowings	1.13%
Effective April 1, 2014 [Member] | Maximum [Member] | Second Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Commitment fee	0.40%
Letter of credit fee	2.13%
Interest rate in excess of Eurocurrency rate applicable to domestic borrowings only	2.13%
Interest rate in excess of base rate, domestic borrowings only	1.13%
Interest rate in excess of Eurocurrency rate of credit agreement for foreign borrowings	2.13%
Effective April 1, 2014 [Member] | Performance Letters Of Credit [Member] | Minimum [Member] | Second Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Letter of credit fee	0.68%
Effective April 1, 2014 [Member] | Performance Letters Of Credit [Member] | Maximum [Member] | Second Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Letter of credit fee	1.28%
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	30-Oct-18
Option to increase revolving commitments under the credit agreement	300,000,000
Swing Line Loans [Member] | Prior and After April 1, 2014 [Member] | Second Amendment [Member] | U S Dollar [Member]	'
Line of Credit Facility [Line Items]	'
Senior secured revolving credit facility	50,000,000
Swing Line Loans [Member] | Prior and After April 1, 2014 [Member] | Second Amendment [Member] | Canadian Dollars [Member]	'
Line of Credit Facility [Line Items]	'
Senior secured revolving credit facility	30,000,000
Swing Line Loans [Member] | Prior and After April 1, 2014 [Member] | Second Amendment [Member] | Australian Dollars [Member]	'
Line of Credit Facility [Line Items]	'
Senior secured revolving credit facility	20,000,000
Performance Letter of Credit [Member] | Minimum [Member] | First Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Letter of credit fee	0.75%
Performance Letter of Credit [Member] | Maximum [Member] | First Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Letter of credit fee	1.50%
Revolving Loans and Letter of Credit in Alternative Currencies [Member] | Prior and After April 1, 2014 [Member] | Second Amendment [Member]	'
Line of Credit Facility [Line Items]	'
Senior secured revolving credit facility	$400,000,000

Equity_Additional_Information_

Equity - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Mar. 26, 2013	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Equity [Line Items]	'	'	'	'
Minimum number of shares that can be exchanged by exchangeable shareholders unless the number of remaining exchangeable shares registered in the name of the holder is less	'	50,000	'	'
Number of shares of Common stock received for each exchangeable share	'	1	'	'
Exchangeable shares exchanged for common stock	409,110	'	'	'
Aggregate authorized amount of common stock to be repurchased	'	$500,000,000	'	'
Reduction in net income as a result of non controlling interests	'	4,240,000	4,776,000	'
Carrying value of the investments held by Quanta in variable interest entities	'	10,900,000	'	7,100,000
Distributions to noncontrolling interests	'	500,000	5,500,000	'
Carrying value of the investment held by noncontrolling interest in variable interest entities	'	10,871,000	'	7,131,000
Series F Preferred Stock [Member]	'	'	'	'
Equity [Line Items]	'	'	'	'
Number of preferred Stock issued to voting trust	'	1	'	'
Common Stock Withheld for Settlement of Employee Tax Liabilities [Member]	'	'	'	'
Equity [Line Items]	'	'	'	'
Treasury stock acquired	'	324,959	296,874	'
Value of treasury stock acquired, cost method	'	11,400,000	9,700,000	'
Stock repurchased during the period	'	$0	'	'

EquityBased_Compensation_Addit

Equity-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Aggregate number of shares of common stock that may be issued for awards pursuant to the 2011 plan	11,750,000	'	'
Aggregate number of shares of common stock that may be issued pursuant to the terms of the 2007 plan	4,000,000	'	'
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	$0.70	$0.60	'
Payment to settle liabilities under compensation plan	2.1	0.5	'
Accrued liabilities under Compensation Plan	0.7	'	2.1
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	1,300,000	1,300,000	'
Vested, shares	1,000,000	900,000	'
Fair value of restricted stock, vested	33.5	24.3	'
Unrecognized compensation cost, related to unvested restricted stock, total	$54.50	'	'
Expected weighted average period to recognize compensation cost on restricted stock and RSUs to be settled in stock (in years)	'2 years 3 months 4 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	'	'

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)

0 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

3 Months Ended

Oct. 09, 2013

Mar. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2011

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2013

Mar. 31, 2014

Dec. 31, 2013

Mar. 31, 2014

Mar. 31, 2014

Apr. 21, 2010

Mar. 31, 2014

Customer

Customer

Customer

Minimum [Member]

Maximum [Member]

Consolidated Revenues [Member]

Consolidated Revenues [Member]

Consolidated Net Position [Member]

Consolidated Net Position [Member]

Customer One [Member]

Customer One [Member]

Customer One [Member]

Other Customer [Member]

Other Customer [Member]

2014 [Member]

Sunrise Powerlink Project [Member]

Sunrise Powerlink Project [Member]

National Gas Company of Trinidad and Tobago Arbitration [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Minimum [Member]

Consolidated Revenues [Member]

mi

Loss Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding capital commitment

'

$13,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitment in next twelve months

'

500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Rent expense related to operating leases

'

34,800,000

24,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum guaranteed residual value

'

329,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated committed capital remainder of current year

'

29,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated committed capital expenditures in 2015

'

400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase commitments related to operating equipment and vehicles

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

18,100,000

'

'

'

Damages sought by Company in arbitration, value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

16,500,000

Loss contingency, damages sought by customer in arbitration counterclaim, value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

79,500,000

Arbitration Damages Liability

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

17,300,000

Interest Payable On Arbitration Damages And Related Attorney Fees Payable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

11,000,000

Written Off of accounts receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,500,000

Selling, general and administrative expenses

'

173,331,000

113,681,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

38,800,000

Length of electrical transmission line to be constructed under contract

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

117

'

Claim for breach of contract

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

165,000,000

'

'

Counterclaim for alleged untimely performance and breach of contract

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

32,000,000

'

'

Percentage of net position

'

'

'

'

'

'

'

'

'

'

'

13.00%

15.00%

'

10.00%

11.00%

'

'

'

'

Number of customer represent ten percent or more of accounts receivable

'

2

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of customers representing ten percent or more of consolidated revenues

'

0

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Concentration risk percentage

'

'

'

'

'

'

'

10.00%

10.00%

10.00%

10.00%

'

'

14.00%

'

'

'

'

'

'

Employer's liability claims subject to deductible per occurrence

'

1,000,000

1,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

General liability insurance claims deductible

'

10,000,000

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Worker's compensation claims per occurrence

'

5,000,000

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Auto liability insurance claims deductible

'

10,000,000

5,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Employee health care benefit plans subject to deductible per claimant

'

375,000

375,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Gross amount accrued for insurance claims

'

163,100,000

'

161,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term insurance claims

'

122,000,000

'

122,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Related insurance recoveries/receivables

'

9,300,000

'

9,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Related insurance recoveries/receivables included in prepaid expenses and other current assets

'

700,000

'

700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Related insurance recoveries/receivables included in other assets net

'

8,600,000

'

8,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Letters of credit outstanding issued under credit facility

'

213,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total amount of outstanding performance bonds

'

2,500,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated cost to complete bonded projects

'

717,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Multi-employer plan withdrawal obligation

'

'

'

'

32,600,000

40,100,000

55,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

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

'

4,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash proceeds deposited in Escrow account

$2,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Contingencies_2

Commitments and Contingencies - Minimum Lease Payments (Detail) (USD $)	Mar. 31, 2014
In Thousands, unless otherwise specified
Commitments And Contingencies Disclosure [Abstract]	'
Remainder of 2014	$47,014
2015	37,193
2016	29,349
2017	21,822
2018	15,250
Thereafter	25,652
Total minimum lease payments	$176,280

Segment_Information_Additional

Segment Information - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]	'	'	'
Number of reportable segments	3	'	'
Property and equipment	$1,269,656,000	'	$1,205,608,000
Canada [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Percentage of foreign revenues	84.00%	96.00%	'
Foreign Operations [Member]	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues from foreign operations	456,200,000	299,200,000	'
Property and equipment	$226,100,000	'	$196,800,000

Segment_Information_Summarized

Segment Information - Summarized Financial Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Revenues	$1,762,574	$1,585,710
Operating income (loss)	90,495	119,291
Depreciation	36,865	31,880
Electric Power [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	1,278,168	1,180,983
Operating income (loss)	144,412	132,550
Depreciation	17,564	14,923
Oil And Gas Infrastructure Services [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	445,857	358,932
Operating income (loss)	-21,172	10,357
Depreciation	13,215	11,265
Fiber Optic Licensing and Other [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Revenues	38,549	45,795
Operating income (loss)	12,109	16,883
Depreciation	4,318	4,051
Corporate and Non-Allocated Costs [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Operating income (loss)	-44,854	-40,499
Depreciation	$1,768	$1,641

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Jun. 30, 2014
			Scenario, Forecast [Member]
Subsequent Event [Line Items]	'	'	'
Cash paid for acquisition	$79,900	$341,100	$3,300
Common stock value	$36,604	$88,895	$2,000