Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2015
Accounting Policies [Abstract]
Principles of Consolidation	*Principles of Consolidation* The consolidated financial statements of Quanta include the accounts of Quanta Services, Inc. and its wholly owned subsidiaries, which are also referred to as its operating units. The consolidated financial statements also include the accounts of certain of Quanta’s investments in joint ventures, which are either consolidated or proportionately consolidated, as discussed in the following summary of significant accounting policies. Investments in affiliated entities in which Quanta does not have a controlling financial interest, but over which Quanta has significant influence, usually because Quanta holds a voting interest of between 20% and 50%, are accounted for using the equity method. All significant intercompany accounts and transactions have been eliminated in consolidation. Unless the context requires otherwise, references to Quanta include Quanta Services, Inc. and its consolidated subsidiaries.
Interim Condensed Consolidated Financial Information	*Interim Condensed Consolidated Financial Information* These unaudited condensed consolidated financial statements have been prepared pursuant to the rules of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures, normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (US GAAP), have been condensed or omitted pursuant to those rules and regulations. Quanta believes that the disclosures made are adequate to make the information presented not misleading. In the opinion of management, all adjustments, consisting only of normal recurring adjustments, necessary to fairly state the financial position, results of operations, comprehensive income and cash flows with respect to the interim condensed consolidated financial statements have been included. The results of operations and comprehensive income for the interim periods are not necessarily indicative of the results for the entire fiscal year. The results of Quanta have historically been subject to significant seasonal fluctuations. Quanta recommends that these unaudited condensed consolidated financial statements be read in conjunction with the audited consolidated financial statements and notes thereto of Quanta and its subsidiaries included in Quanta’s Annual Report on Form 10-K for the year ended December 31, 2014, which was filed with the SEC on March 2, 2015.
Use of Estimates and Assumptions	*Use of Estimates and Assumptions* The preparation of financial statements in conformity with US GAAP requires the use of estimates and assumptions by management in determining the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities known to exist as of the date the financial statements are published, and the reported amounts of revenues and expenses recognized during the periods presented. Quanta reviews all significant estimates affecting its consolidated financial statements on a recurring basis and records the effect of any necessary adjustments prior to their publication. Judgments and estimates are based on Quanta’s beliefs and assumptions derived from information available at the time such judgments and estimates are made. Uncertainties with respect to such estimates and assumptions are inherent in the preparation of financial statements. Estimates are primarily used in Quanta’s assessment of the allowance for doubtful accounts, valuation of inventory, useful lives of assets, fair value assumptions in analyzing goodwill, other intangibles and long-lived asset impairments, equity and other investments, loan receivables, purchase price allocations, liabilities for self-insured and other claims and guarantees, multi-employer pension plan withdrawal liabilities, revenue recognition for construction contracts inclusive of contractual change orders and claims, share-based compensation, operating results of reportable segments, as well as the provision for income taxes and the calculation of uncertain tax positions.
Cash and Cash Equivalents	*Cash and Cash Equivalents* Quanta had cash and cash equivalents of $65.4 million and $190.5 million as of June 30, 2015 and December 31, 2014. Cash consisting of interest-bearing demand deposits is carried at cost, which approximates fair value. Quanta considers all highly liquid investments with an original maturity of three months or less at the time of purchase to be cash equivalents, which are carried at fair value. At June 30, 2015 and December 31, 2014, cash equivalents were $4.7 million and $107.6 million, and consisted primarily of money market mutual funds and are discussed further in Fair Value Measurements below. As of June 30, 2015 and December 31, 2014, cash and cash equivalents held in domestic bank accounts were approximately $29.1 million and $127.2 million, and cash and cash equivalents held in foreign bank accounts were approximately $36.3 million and $63.3 million. As of June 30, 2015 and December 31, 2014, cash and cash equivalents held by Quanta’s investments in joint ventures, which are either consolidated or proportionately consolidated, were approximately $13.6 million and $19.1 million. Cash and cash equivalents held by the joint ventures are available to support the operations of the related joint ventures, and Quanta does not have access to that cash for its other operations. Under the terms of the partnership agreements, Quanta generally has no right to the joint ventures’ cash other than participating in distributions and in the event of dissolution.
Current and Long-Term Accounts and Notes Receivable and Allowance for Doubtful Accounts	*Current and Long-Term Accounts and Notes Receivable and Allowance for Doubtful Accounts* Quanta provides an allowance for doubtful accounts when collection of an account or note receivable is considered doubtful, and receivables are written off against the allowance when deemed uncollectible. Inherent in the assessment of the allowance for doubtful accounts are certain judgments and estimates regarding, among other factors, the customer’s access to capital, the customer’s willingness or ability to pay, general economic and market conditions, the ongoing relationship with the customer and uncertainties related to the resolution of disputed matters. Quanta considers accounts receivable delinquent after 30 days but does not generally include delinquent accounts in its analysis of the allowance for doubtful accounts unless the accounts receivable have been outstanding for at least 90 days. In addition to balances that have been outstanding for 90 days or more, Quanta also includes accounts receivable balances that relate to customers in bankruptcy or with other known difficulties in its analysis of the allowance for doubtful accounts. Material changes in Quanta’s customers’ business or cash flows, which may be impacted by negative economic and market conditions, could affect Quanta’s ability to collect amounts due from them. As of June 30, 2015 and December 31, 2014, Quanta had allowances for doubtful accounts on current receivables of approximately $6.0 million and $6.2 million. Long-term accounts receivable are included within other assets, net on the consolidated balance sheets. Should customers experience financial difficulties or file for bankruptcy, or should anticipated recoveries relating to receivables in existing bankruptcies or other workout situations fail to materialize, Quanta could experience reduced cash flows and losses in excess of current allowances provided. The balances billed but not paid by customers pursuant to retainage provisions in certain contracts are generally due upon completion of the contracts and acceptance by the customer. Based on Quanta’s experience with similar contracts in recent years, the majority of the retainage balances at each balance sheet date are expected to be collected within the next twelve months. Current retainage balances as of June 30, 2015 and December 31, 2014 were approximately $284.3 million and $307.3 million, and were included in accounts receivable. Retainage balances with settlement dates beyond the next twelve months were included in other assets, net, and as of June 30, 2015 and December 31, 2014 were $30.8 million and $19.6 million. Within accounts receivable, Quanta recognizes unbilled receivables in circumstances such as when revenues have been earned and recorded but the amount cannot be billed under the terms of the contract until a later date; costs have been incurred but are yet to be billed under cost-reimbursement type contracts; or amounts arise from routine lags in billing (for example, work completed one month but not billed until the next month). These balances do not include revenues accrued for work performed under fixed-price contracts as these amounts are recorded as costs and estimated earnings in excess of billings on uncompleted contracts. At June 30, 2015 and December 31, 2014, the balances of unbilled receivables included in accounts receivable were approximately $229.1 million and $163.1 million.
Goodwill and Other Intangibles	*Goodwill and Other Intangibles* Quanta has recorded goodwill in connection with its historical acquisitions of companies. Upon acquisition, these companies were either combined into one of Quanta’s existing operating units or managed on a stand-alone basis as an individual operating unit. Goodwill recorded in connection with these acquisitions is subject to an annual assessment for impairment, which Quanta performs at the operating unit level for each operating unit that carries a balance of goodwill. Each of Quanta’s operating units is organized into one of two internal divisions: the Electric Power Division and the Oil and Gas Infrastructure Division. As most of the companies acquired by Quanta provide multiple types of services for multiple types of customers, these divisional designations are based on the predominant type of work performed by each operating unit at the point in time the divisional designation is made. Goodwill is required to be measured for impairment at the reporting unit level, which represents the operating segment level or one level below the operating segment level for which discrete financial information is available. Quanta has determined that its individual operating units represent its reporting units for the purpose of assessing goodwill impairments. Quanta has the option to first assess qualitative factors to determine whether it is necessary to perform the two-step fair value-based impairment test described below. If Quanta believes that, as a result of its qualitative assessment, it is more likely than not that the fair value of a reporting unit is less than its carrying amount, the quantitative impairment test is required. Otherwise, no further testing is required. Quanta can choose to perform the qualitative assessment on none, some or all of its reporting units. Quanta can also bypass the qualitative assessment for any reporting unit in any period and proceed directly to step one of the impairment test, and then resume the qualitative assessment in any subsequent period. Qualitative indicators, including deterioration in macroeconomic conditions, declining financial performance, or a sustained decrease in share price, among other things, may trigger the need for annual or interim impairment testing of goodwill associated with one or all of the reporting units. Quanta’s goodwill impairment assessment is performed at year-end, or more frequently if events or circumstances arise which indicate that goodwill may be impaired. For instance, a decrease in Quanta’s market capitalization below book value, a significant change in business climate or loss of a significant customer, as well as the qualitative indicators referenced above, may trigger the need for interim impairment testing of goodwill for one or all of its reporting units. The first step of the two-step fair value-based test involves comparing the fair value of each of Quanta’s reporting units with its carrying value, including goodwill. If the carrying value of the reporting unit exceeds its fair value, the second step is performed. The second step compares the carrying amount of the reporting unit’s goodwill to the implied fair value of its goodwill. If the implied fair value of goodwill is less than the carrying amount, an impairment loss would be recorded as a reduction to goodwill with a corresponding charge to operating expense. Quanta determines the fair value of its reporting units using a weighted combination of the discounted cash flow, market multiple and market capitalization valuation approaches, with heavier weighting on the discounted cash flow method, as in management’s opinion this method currently results in the most accurate calculation of a reporting unit’s fair value. Determining the fair value of a reporting unit requires judgment and the use of significant estimates and assumptions. Such estimates and assumptions include revenue growth rates, operating margins, discount rates, weighted average costs of capital and future market conditions, among others. Quanta believes the estimates and assumptions used in its impairment assessments are reasonable and based on available market information, but variations in any of the assumptions could result in materially different calculations of fair value and determinations of whether or not an impairment is indicated. Under the discounted cash flow method, Quanta determines fair value based on the estimated future cash flows of each reporting unit, discounted to present value using risk-adjusted industry discount rates, which reflect the overall level of inherent risk of a reporting unit and the rate of return an outside investor would expect to earn. Cash flow projections are derived from budgeted amounts and operating forecasts (typically a one-year model) plus an estimate of later period cash flows, all of which are evaluated by management. Subsequent period cash flows are developed for each reporting unit using growth rates that management believes are reasonably likely to occur, along with a terminal value derived from the reporting unit’s earnings before interest, taxes, depreciation and amortization (EBITDA). The EBITDA multiples for each reporting unit are based on trailing twelve-month comparable industry data. Under the market multiple and market capitalization approaches, Quanta determines the estimated fair value of each of its reporting units by applying transaction multiples to each reporting unit’s projected EBITDA and then averaging that estimate with similar historical calculations using either a one, two or three year average. For the market capitalization approach, Quanta adds a reasonable control premium, which is estimated as the premium that would be received in a sale of the reporting unit in an orderly transaction between market participants. For recently acquired reporting units, a step one impairment test may indicate an implied fair value that is substantially similar to the reporting unit’s carrying value. Such similarities in value are generally an indication that management’s estimates of future cash flows associated with the recently acquired reporting unit remain relatively consistent with the assumptions that were used to derive its initial fair value. During the fourth quarter of 2014, a two-step fair-value based goodwill impairment analysis was performed for each of Quanta’s reporting units, and no reporting units were evaluated solely on a qualitative basis. The analysis indicated that the implied fair value of each of Quanta’s reporting units, other than recently acquired reporting units, was substantially in excess of its carrying value. Following the analysis, management concluded that no impairment was indicated at any reporting unit. As discussed generally above, when evaluating the 2014 step one impairment test results, management considered many factors in determining whether or not an impairment of goodwill for any reporting unit was reasonably likely to occur in future periods, including future market conditions and the economic environment in which Quanta’s reporting units were operating. Additionally, management considered the sensitivity of its fair value estimates to changes in certain valuation assumptions and, after giving consideration to at least a 10% decrease in the fair value of each of Quanta’s reporting units, the results of the assessment at December 31, 2014 did not change. However, circumstances such as market declines, unfavorable economic conditions, the loss of a major customer or other factors could impact the valuation of goodwill in future periods. Quanta’s intangible assets include customer relationships, backlog, trade names, non-compete agreements, patented rights and developed technology, all subject to amortization. The value of customer relationships is estimated as of the date a business is acquired based on the value-in-use concept utilizing the income approach, specifically the excess earnings method. The excess earnings analysis consists of discounting to present value the projected cash flows attributable to the customer relationships, with consideration given to customer contract renewals and estimated customer attrition rates, the importance or lack thereof of existing customer relationships to Quanta’s business plan, income taxes and required rates of return. Quanta values backlog for acquired businesses as of the acquisition date based upon the contractual nature of the backlog within each service line, using the income approach to discount back to present value the cash flows attributable to the backlog. The value of trade names is estimated using the relief-from-royalty method of the income approach. This approach is based on the assumption that in lieu of ownership, a company would be willing to pay a royalty in order to exploit the related benefits of this intangible asset. Quanta amortizes intangible assets based upon the estimated consumption of the economic benefits of each intangible asset, or on a straight-line basis if the pattern of economic benefits consumption cannot otherwise be reliably estimated. Intangible assets subject to amortization are reviewed for impairment and are tested for recoverability whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. For instance, a significant change in business climate or a loss of a significant customer, among other things, may trigger the need for interim impairment testing of intangible assets. An impairment loss would be recognized if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its fair value.
Investments in Affiliates and Other Entities	*Investments in Affiliates and Other Entities* In the normal course of business, Quanta enters into various types of investment arrangements, each having unique terms and conditions. These investments may include equity interests held by Quanta in business entities, including general or limited partnerships, contractual joint ventures, or other forms of equity participation. These investments may also include Quanta’s participation in different financing structures such as the extension of loans to project specific entities, the acquisition of convertible notes issued by project specific entities, or other strategic financing arrangements. Quanta determines whether such investments involve a variable interest entity (VIE) based on the characteristics of the subject entity. If the entity is determined to be a VIE, then management determines if Quanta is the primary beneficiary of the entity and whether or not consolidation of the VIE is required. The primary beneficiary consolidating the VIE must normally have both (i) the power to direct the activities of a VIE that most significantly affect the VIE’s economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE, in either case that could potentially be significant to the VIE. When Quanta is deemed to be the primary beneficiary, the VIE is consolidated and the other party’s equity interest in the VIE is accounted for as a non-controlling interest. In cases where Quanta determines that it has an undivided interest in the assets, liabilities, revenues and profits of an unincorporated VIE (e.g., a general partnership interest), such amounts are consolidated on a basis proportional to Quanta’s ownership interest in the unincorporated entity. Investments in entities of which Quanta is not the primary beneficiary, but over which Quanta has the ability to exercise significant influence, are accounted for using the equity method of accounting. Quanta’s share of net income or losses from unconsolidated equity investments is included in equity in earnings (losses) of unconsolidated affiliates in the consolidated statements of operations when applicable. Equity investments are reviewed for impairment by assessing whether any decline in the fair value of the investment below the carrying value is other than temporary. In making this determination, factors such as the ability to recover the carrying amount of the investment and the inability of the investee to sustain an earnings capacity are evaluated in determining whether a loss in value should be recognized. Any impairment losses would be recognized in other expense. Equity method investments are carried at original cost and are included in other assets, net in the consolidated balance sheet and are adjusted for Quanta’s proportionate share of the investees’ income, losses and distributions.
Revenue Recognition	*Revenue Recognition* Through its Electric Power Infrastructure Services and Oil and Gas Infrastructure Services segments, Quanta designs, installs and maintains networks for customers in the electric power and oil and gas industries. These services may be provided pursuant to master service agreements, repair and maintenance contracts and fixed price and non-fixed price installation contracts. Pricing under these contracts may be competitive unit price, cost-plus/hourly (or time and materials basis) or fixed price (or lump sum basis), and the final terms and prices of these contracts are frequently negotiated with the customer. Under unit-based contracts, the utilization of an output-based measurement is appropriate for revenue recognition. Under these contracts, Quanta recognizes revenue as units are completed based on pricing established between Quanta and the customer for each unit of delivery, which best reflects the pattern in which the obligation to the customer is fulfilled. Under cost-plus/hourly and time and materials type contracts, Quanta recognizes revenue on an input basis, as labor hours are incurred and services are performed. Revenues from fixed price contracts are recognized using the percentage-of-completion method, measured by the percentage of costs incurred to date to total estimated costs for each contract. These contracts provide for a fixed amount of revenues for the entire project. Such contracts provide that the customer accept completion of progress to date and compensate Quanta for services rendered, which may be measured in terms of units installed, hours expended or some other measure of progress. Contract costs include all direct materials, labor and subcontract costs and those indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and depreciation costs. Much of the material associated with Quanta’s work is owner-furnished and is therefore not included in contract revenues and costs. The cost estimation process is based on professional knowledge and experience of Quanta’s engineers, project managers and financial professionals. Changes in job performance, job conditions and final contract settlements are factors that influence management’s assessment of total contract value and the total estimated costs to complete those contracts and therefore Quanta’s profit recognition. Changes in these factors may result in revisions to costs and income, and their effects are recognized in the period in which the revisions are determined. These factors are routinely evaluated on a project by project basis throughout the project term, and the impact of corresponding revisions in management’s estimates of contract value, contract cost and contract profit are recorded as necessary in the period in which the revisions are determined. Provisions for losses on uncompleted contracts are made in the period in which such losses are determined to be probable and the amount can be reasonably estimated. Quanta’s operating results for the six months ended June 30, 2015 and 2014 were impacted by less than 5% as a result of changes in contract estimates related to projects that were in progress at December 31, 2014 and 2013. The current asset “Costs and estimated earnings in excess of billings on uncompleted contracts” represents revenues recognized in excess of amounts billed for fixed price contracts. The current liability “Billings in excess of costs and estimated earnings on uncompleted contracts” represents billings in excess of revenues recognized for fixed price contracts. Quanta may incur costs subject to change orders, whether approved or unapproved by the customer, and/or claims related to certain contracts. Quanta determines the probability that such costs will be recovered based upon evidence such as past practices with the customer, specific discussions or preliminary negotiations with the customer or verbal approvals. Quanta treats items as a cost of contract performance in the period incurred if it is not probable that the costs will be recovered or will recognize revenue if it is probable that the contract price will be adjusted and can be reliably estimated. As of June 30, 2015 and December 31, 2014, Quanta had approximately $134.7 million and $106.8 million of change orders and/or claims that had been included as contract price adjustments on certain contracts which were in the process of being negotiated in the normal course of business. These aggregate contract price adjustments represent management’s best estimate of additional contract revenues which have been earned and which management believes are probable of collection. The amounts ultimately realized by Quanta upon final acceptance by its customers could be higher or lower than such estimated amounts.
Income Taxes	*Income Taxes* Quanta follows the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recorded for future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the underlying assets or liabilities are recovered or settled. Quanta regularly evaluates valuation allowances established for deferred tax assets for which future realization is uncertain. The estimation of required valuation allowances includes estimates of future taxable income. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Quanta considers projected future taxable income and tax planning strategies in making this assessment. If actual future taxable income differs from these estimates, Quanta may not realize deferred tax assets to the extent estimated. Quanta records reserves for income taxes related to certain tax positions in those instances where Quanta considers it more likely than not that additional taxes may be due in excess of amounts reflected on income tax returns filed. When recording reserves for expected tax consequences of uncertain positions, Quanta assumes that taxing authorities have full knowledge of the position and all relevant facts. Quanta continually reviews exposure to additional tax obligations, and as further information is known or events occur, changes in tax reserves may be recorded. To the extent interest and penalties may be assessed by taxing authorities on any underpayment of income tax, such amounts have been accrued and are classified in the provision for income taxes. As of June 30, 2015, the total amount of unrecognized tax benefits relating to uncertain tax positions was $52.7 million, an increase from December 31, 2014 of $1.8 million. This increase in unrecognized tax benefits resulted primarily from a $2.2 million increase due to tax positions expected to be taken for 2015, partially offset by a $0.4 million decrease due to audit settlements. Quanta is currently under examination by the Internal Revenue Service (IRS) for tax years 2011 and 2012 and remains open to examination by the IRS for tax years 2013 and 2014, as these statute of limitations periods have not yet expired. Additionally, certain subsidiaries are under examination by various U.S. state, Canadian and other foreign tax authorities for multiple periods. Quanta believes it is reasonably possible that within the next 12 months unrecognized tax benefits may decrease by up to $10.3 million as a result of settlement of these examinations or as a result of the expiration of certain statute of limitations periods. The income tax laws and regulations are voluminous and are often ambiguous. As such, Quanta is required to make many subjective assumptions and judgments regarding its tax positions that could materially affect amounts recognized in its future consolidated balance sheets and statements of operations and comprehensive income.
Earnings Per Share	*Earnings Per Share* Basic earnings per share is computed using the weighted average number of common shares outstanding during the period, and diluted earnings per share is computed using the weighted average number of common shares outstanding during the period adjusted for all potentially dilutive common stock equivalents, except in cases where the effect of the common stock equivalents would be antidilutive.
Self-Insurance	*Self-Insurance* Quanta is insured for employer’s liability, general liability, auto liability and workers’ compensation claims. Under these programs, the deductibles for general liability and auto liability were $10.0 million per occurrence, the deductible for workers’ compensation was $5.0 million per occurrence, and the deductible for employer’s liability was $1.0 million per occurrence for the 2015-2016 and 2014-2015 policy years. Quanta is generally self-insured for all claims that do not exceed the amount of the applicable deductible. Quanta also has employee health care benefit plans for most employees not subject to collective bargaining agreements, of which the primary plan is subject to a deductible of $375,000 per claimant per year. Losses under all of these insurance programs are accrued based upon Quanta’s estimate of the ultimate liability for claims reported and an estimate of claims incurred but not reported, with assistance from third-party actuaries. These insurance liabilities are difficult to assess and estimate due to unknown factors, including the severity of an injury, the extent of damage, the determination of Quanta’s liability in proportion to other parties and the number of incidents not reported. The accruals are based upon known facts and historical trends, and management believes such accruals are adequate.
Collective Bargaining Agreements	*Collective Bargaining Agreements* Some of Quanta’s operating units are parties to various collective bargaining agreements with unions that represent certain of their employees. The collective bargaining agreements expire at various times and have typically been renegotiated and renewed on terms similar to those in the expiring agreements. The agreements require the operating units to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to multi-employer pension plans and employee benefit trusts. Quanta’s multi-employer pension plan contribution rates generally are specified in the collective bargaining agreements (usually on an annual basis), and contributions are made to the plans on a “pay-as-you-go” basis based on its union employee payrolls. The location and number of union employees that Quanta employs at any given time and the plans in which they may participate vary depending on the projects Quanta has ongoing at that time and the need for union resources in connection with those projects. Therefore, Quanta is unable to accurately predict the union employee payroll and the amount of the resulting multi-employer pension plan contribution obligation for future periods.
Stock-Based Compensation	*Stock-Based Compensation* Quanta recognizes compensation expense for restricted stock, restricted stock units (RSUs) and performance units to be settled in common stock based on the fair value of the awards granted at the date of grant, net of estimated forfeitures. The fair value of restricted stock awards, RSUs and performance units to be settled in common stock is determined based on the number of shares, RSUs or performance units granted and the closing price of Quanta’s common stock on the date of grant. An estimate of future forfeitures is required in determining the period expense. Quanta uses historical data to estimate the forfeiture rate; however, these estimates are subject to change and may impact the value that will ultimately be realized as compensation expense. The resulting compensation expense from discretionary awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period, while compensation expense from performance-based awards is recognized using the graded vesting method over the requisite service period. The cash flows resulting from the tax deductions in excess of the compensation expense recognized for restricted stock, RSUs and performance units to be settled in common stock and stock options (excess tax benefit) are classified as financing cash flows. Compensation expense associated with liability based awards, such as RSUs that are expected to or may settle in cash, is recognized based on a remeasurement of the fair value of the award at the end of each reporting period. Upon settlement, the holders receive for each RSU an amount in cash equal to the fair market value on the settlement date of one share of Quanta common stock, as specified in the applicable award agreement. For additional information on Quanta’s restricted stock, RSU and performance unit awards, see Note 10.
Functional Currency and Translation of Financial Statements	*Functional Currency and Translation of Financial Statements* The U.S. dollar is the functional currency for the majority of Quanta’s operations, which are primarily located within the United States. The functional currency for Quanta’s foreign operations, which are primarily located in Canada and Australia, is typically the currency of the country in which the foreign operating unit is located. Generally, the currency in which the operating unit transacts the majority of its activities, including billings, financing, payroll and other expenditures, would be considered the functional currency. The treatment of foreign currency translation gains or losses is dependent upon management’s determination of the functional currency of each operating unit, which involves consideration of all relevant economic facts and circumstances affecting the operating unit. In preparing the consolidated financial statements, Quanta translates the financial statements of its foreign operating units from their functional currency into U.S. dollars. Statements of operations, comprehensive income and cash flows are translated at average monthly rates, while balance sheets are translated at month-end exchange rates. This results in translation gains or losses, which are included as a separate component of equity under the caption “Accumulated other comprehensive income (loss).” Gains and losses arising from transactions which are not denominated in the operating units’ functional currencies are included within other income (expense) in the statements of operations.
Comprehensive Income	*Comprehensive Income* Components of comprehensive income include all changes in equity during a period except those resulting from changes in Quanta’s capital related accounts. Quanta records other comprehensive income (loss) for foreign currency translation adjustments related to its foreign operations and for other revenues, expenses, gains and losses that are included in comprehensive income, but excluded from net income.
Litigation Costs and Reserves	*Litigation Costs and Reserves* Quanta records reserves when it is probable that a liability has been incurred and the amount of loss can be reasonably estimated. Costs incurred for litigation are expensed as incurred. Further details are presented in Note 11.
Fair Value Measurements	*Fair Value Measurements* The carrying values of cash equivalents, accounts receivable, accounts payable and accrued expenses approximate fair value due to the short-term nature of these instruments. The carrying value of variable rate debt also approximates fair value. For disclosure purposes, qualifying assets and liabilities are categorized into three broad levels based on the priority of the inputs used to determine their fair values. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). All of Quanta’s cash equivalents were categorized as Level 1 assets at June 30, 2015 and December 31, 2014, as all values were based on unadjusted quoted prices for identical assets in an active market that Quanta has the ability to access. In connection with Quanta’s acquisitions, identifiable intangible assets acquired include goodwill, backlog, customer relationships, trade names, covenants not-to-compete, patented rights and developed technology. Quanta utilizes the fair value premise as the primary basis for its valuation procedures, which is a market-based approach to determine the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Quanta periodically engages the services of an independent valuation firm when a new business is acquired to assist management with this valuation process, including assistance with the selection of appropriate valuation methodologies and the development of market-based valuation assumptions. Based on these considerations, management utilizes various valuation methods, including an income approach, a market approach and a cost approach, to determine the fair value of intangible assets acquired based on the appropriateness of each method in relation to the type of asset being valued. The assumptions used in these valuation methods are analyzed and compared, where possible, to available market data, such as industry-based weighted average costs of capital and discount rates, trade name royalty rates, public company valuation multiples and recent market acquisition multiples. In accordance with its annual impairment test during the quarter ended December 31, 2014, the carrying amounts of such assets, including goodwill, were compared to their fair values. The level of inputs used for these fair value measurements is the lowest level (Level 3). Quanta uses the assistance of third party specialists to develop valuation assumptions. Quanta believes that these valuation methods appropriately represent the methods that would be used by other market participants in determining fair value. Quanta also uses fair value measurements in connection with the valuation of its investments in private company equity interests and financing instruments. These valuations require significant management judgment due to the absence of quoted market prices, the inherent lack of liquidity and the long-term nature of such assets. Typically, the initial costs of these investments are considered to represent fair market value, as such amounts are negotiated between willing market participants. On a quarterly basis, Quanta performs an evaluation of its investments to determine if an other-than-temporary decline in the value of each investment has occurred and whether the recorded amount of each investment will be realizable. If an other-than-temporary decline in the value of an investment occurs, a fair value analysis would be performed to determine the degree to which the investment was impaired and a corresponding charge to earnings would be recorded during the period. These types of fair market value assessments are similar to other nonrecurring fair value measures used by Quanta, which include the use of significant judgment and available relevant market data. Such market data may include observations of the valuation of comparable companies, risk adjusted discount rates and an evaluation of the expected performance of the underlying portfolio asset, including historical and projected levels of profitability or cash flows. In addition, a variety of additional factors may be reviewed by management, including, but not limited to, contemporaneous financing and sales transactions with third parties, changes in market outlook and the third-party financing environment.
Adoption of New Accounting Pronouncements	*Adoption of New Accounting Pronouncements* In April 2014, the Financial Accounting Standards Board (FASB) issued an update that changes the requirement for reporting discontinued operations. A disposal of a component of an entity or a group of components of an entity will be required to be reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results when the entity or group of components of an entity meets the criteria to be classified as held for sale or when it is disposed of by sale or other than by sale. The update also requires additional disclosures about discontinued operations, a disposal of an individually significant component of an entity that does not qualify for discontinued operations presentation in the financial statements, and an entity’s significant continuing involvement with a discontinued operation. Quanta adopted this guidance effective January 1, 2015 and has incorporated the new requirements into its presentation of the disposition of the fiber optic licensing operations as discontinued operations as of June 30, 2015.
Accounting Standards Not Yet Adopted	*Accounting Standards Not Yet Adopted* In May 2014, the FASB issued an update that supersedes most current revenue recognition guidance as well as some cost recognition guidance. The update requires that an entity recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This update also requires new qualitative and quantitative disclosures about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments, information about contract balances and performance obligations, and assets recognized from costs incurred to obtain or fulfill a contract. On July 9, 2015, the FASB affirmed its proposal to defer the effective date until fiscal years beginning on or after December 15, 2017. The guidance can be applied on a full retrospective or modified retrospective basis whereby the entity records a cumulative effect of initially applying this update at the date of initial application. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and is planning to adopt this guidance effective January 1, 2018. In August 2014, the FASB issued guidance to address the diversity in practice in determining when there is substantial doubt about an entity’s ability to continue as a going concern and when and how an entity must disclose certain relevant conditions and events. This update requires an entity to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity’s ability to continue as a going concern for a period of one year after the date that the financial statements are issued (or available to be issued). If such conditions or events exist, an entity should disclose that there is substantial doubt about the entity’s ability to continue as a going concern for a period of one year after the date that the financial statements are issued (or available to be issued), along with the principal conditions or events that raise substantial doubt, management’s evaluation of the significance of those conditions or events in relation to the entity’s ability to meet its obligations and management’s plans that are intended to mitigate those conditions or events. The guidance is effective for annual and interim periods ending after December 15, 2016. This guidance will impact the disclosure and presentation of any substantial doubt by Quanta about its ability to continue as a going concern, if such substantial doubt were to exist. Quanta will adopt this guidance effective January 1, 2017. In February 2015, the FASB issued an update which amends existing consolidation guidance, including amending the guidance related to determining whether an entity is a variable interest entity. The update is effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The guidance may be applied using a modified retrospective approach whereby the entity records a cumulative effect of adoption at the beginning of the fiscal year of initial application. A reporting entity may also apply the amendments on a full retrospective basis. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements. In April 2015, the FASB issued an update that requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with the presentation of debt discounts and premiums. The standard is effective for interim and annual reporting periods beginning after December 15, 2015, although early adoption is permitted. The update is required to be adopted retroactively for all periods presented. The adoption of the update is not expected to have a significant impact on Quanta’s consolidated financial statements or related disclosures. Quanta will adopt this guidance effective January 1, 2016.
Repurchase of Common Stock	During the fourth quarter of 2013, Quanta’s board of directors approved a stock repurchase program authorizing Quanta to purchase, from time to time through December 31, 2016, up to $500.0 million of its outstanding common stock. During the three and six months ended June 30, 2015, Quanta purchased 5.8 million and 12.5 million shares of its common stock under this program at a cost of $172.3 million and $354.3 million. As of June 30, 2015, Quanta had purchased an aggregate of approximately 15.5 million shares of its common stock under this program at a cost of $447.8 million. The shares and the related cost to acquire them have been accounted for as an adjustment to the balance of treasury stock. In the third quarter of 2015, Quanta completed this stock repurchase program, purchasing an additional 1.8 million shares for a cost of $52.2 million. During the third quarter of 2015, Quanta’s board of directors approved a stock repurchase program authorizing Quanta to purchase, from time to time through February 28, 2017, up to $1.25 billion of its outstanding common stock. Repurchases can be made in open market or privately negotiated transactions, including pursuant to an accelerated share repurchase arrangement, an issuer repurchase plan or otherwise, at management’s discretion, based on market and business conditions, applicable contractual and legal requirements and other factors. This program does not obligate Quanta to acquire any specific amount of common stock and may be modified or terminated by Quanta’s board of directors at any time at its sole discretion and without notice.
Segment Reporting	Quanta presents its operations under two reportable segments: (1) Electric Power Infrastructure Services and (2) Oil and Gas Infrastructure Services. This structure is generally based on the broad end-user markets for Quanta’s services. See Note 1 for additional information regarding Quanta’s reportable segments. Quanta’s segment results are derived from the types of services provided across its operating units in each of the end user markets described above. Quanta’s entrepreneurial business model allows each of its operating units to serve the same or similar customers and to provide a range of services across end user markets. Quanta’s operating units are organized into one of two internal divisions, namely, the Electric Power Division and the Oil and Gas Infrastructure Division. These internal divisions are closely aligned with the reportable segments described above based on their operating units’ predominant type of work. Reportable segment information, including revenues and operating income by type of work, is gathered from each operating unit for the purpose of evaluating segment performance in support of Quanta’s market strategies. These classifications of Quanta’s operating unit revenues by type of work for segment reporting purposes can at times require judgment on the part of management. Quanta’s operating units may perform joint infrastructure service projects for customers in multiple industries, deliver multiple types of network services under a single customer contract or provide service across industries, for example, joint trenching projects to install distribution lines for electric power and natural gas customers. In addition, Quanta’s integrated operations and common administrative support at each of its operating units require that certain allocations of shared and indirect costs, such as facility costs and indirect operating expenses, including depreciation and general and administrative costs, be made to determine operating segment profitability. Corporate costs, such as payroll and benefits, employee travel expenses, facility costs, professional fees, acquisition costs and amortization related to certain intangible assets are not allocated. Separate measures of Quanta’s assets and cash flows by reportable segment, including capital expenditures, are not produced or utilized by management to evaluate segment performance. Quanta’s fixed assets, which are held at the operating unit level, include operating machinery, equipment and vehicles, as well as office equipment, buildings and leasehold improvements, and are used on an interchangeable basis across its reportable segments. As such, for reporting purposes, total depreciation expense is allocated each quarter among Quanta’s reportable segments based on the ratio of each reportable segment’s revenue contribution to consolidated revenues.