| Summary of Significant Accounting Policies (Policies) | 6 Months Ended |
| Jun. 30, 2018 |
| Accounting Policies [Abstract] | |
| Principles of Consolidation | Principles of Consolidation The condensed 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 condensed 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 U.S. Securities and Exchange Commission (SEC). Certain information and footnote disclosures, normally included in annual financial statements prepared in accordance with U.S. Generally Accepted Accounting Principles (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 consolidated subsidiaries included in Quanta’s Annual Report on Form 10-K for the year ended December 31, 2017 , which was filed with the SEC on February 28, 2018 . |
| Reclassifications | Reclassifications Quanta reclassified certain prior period amounts related to restricted cash and proceeds from the settlement of insurance claims related to property and equipment in the accompanying condensed consolidated statements of cash flows to conform to the current period presentation under recently adopted accounting updates. See Note 3 for further details regarding these updates. Certain reclassifications have also been made to Quanta’s condensed consolidated statements of operations for 2017 to conform to classifications for 2018. Additionally, the amounts previously reported as “Costs and estimated earnings in excess of billings on uncompleted contracts” and “Billings in excess of costs and estimated earnings on uncompleted contracts” on Quanta’s condensed consolidated balance sheets have been included in the newly titled “Contract assets” and “Contract liabilities” in accordance with the newly adopted revenue recognition guidance discussed below and in Note 3. |
| 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, acquisition-related contingent consideration liabilities, liabilities for insurance and other claims and guarantees, multiemployer pension plan withdrawal liabilities, contingent 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 $120.4 million and $138.3 million as of June 30, 2018 and December 31, 2017 . 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, 2018 and December 31, 2017 , cash equivalents were $55.1 million and $7.1 million , and consisted primarily of money market investments and money market mutual funds and are discussed further in Fair Value Measurements below. As of June 30, 2018 and December 31, 2017 , cash and cash equivalents held in domestic bank accounts were $79.6 million and $83.1 million , and cash and cash equivalents held in foreign bank accounts were $40.8 million and $55.2 million . As of June 30, 2018 and December 31, 2017 , cash and cash equivalents held by joint ventures, which are either consolidated or proportionately consolidated, were $11.6 million and $16.7 million , of which $11.2 million and $10.0 million related to domestic joint ventures. Cash and cash equivalents held by the joint ventures are available to support joint venture operations, but Quanta cannot utilize those assets to support its other operations. Quanta generally has no right to the joint ventures’ cash and cash equivalents 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. 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 customers’ business or cash flows, which may be impacted by negative economic and market conditions, could affect Quanta’s ability to collect amounts due. As of June 30, 2018 and December 31, 2017 , Quanta had allowances for doubtful accounts on current receivables of $4.8 million and $4.5 million . Long-term accounts receivable are included within “Other assets, net” in the accompanying condensed 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. Some contracts allow customers to withhold a small percentage of billings pursuant to retainage provisions, and such amounts 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, 2018 and December 31, 2017 were $254.8 million and $300.5 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 June 30, 2018 and December 31, 2017 were $90.7 million and $41.9 million . Quanta recognizes unbilled receivables within “Accounts receivable” in certain 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 revenue recognized for work performed under fixed-price contracts, as these amounts are recorded as “Contract assets.” At June 30, 2018 and December 31, 2017 , the balances of unbilled receivables included in “Accounts receivable” were $433.5 million and $303.9 million . |
| Goodwill and Other Intangibles | Goodwill Quanta has recorded goodwill in connection with its historical acquisitions of businesses. Upon acquisition, these businesses were either combined into one of Quanta’s existing operating units or managed on a stand-alone basis as an individual operating unit. An annual assessment for impairment is performed for each operating unit that carries a balance of goodwill. Quanta’s operating units are organized into one of two internal divisions: the Electric Power Infrastructure Services Division and the Oil and Gas Infrastructure Services Division. As most of the companies acquired by Quanta provide multiple types of services for multiple types of customers, these divisional designations are based on the predominant type of work performed by an 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. An annual, or interim, goodwill impairment test is performed by comparing the fair value of a reporting unit with its carrying amount and recognizing an impairment charge for the amount by which the carrying amount exceeds the fair value. The income tax effect associated with an impairment of tax deductible goodwill is also considered in the measurement of the goodwill impairment. Quanta has the option to first assess qualitative factors to determine whether it is necessary to perform the quantitative 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. 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 the quantitative 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 annual goodwill impairment assessment is performed in the fourth quarter of its fiscal year, 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 a reporting unit. The quantitative impairment test involves comparing the fair value of each of Quanta’s reporting units with its carrying amount, including goodwill. If the carrying amount of a reporting unit exceeds its fair value, an impairment loss is recorded as a reduction to goodwill with a corresponding charge to “Asset impairment charges” in the consolidated statements of operations. Any goodwill impairment is limited to the total amount of goodwill allocated to that reporting unit. 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 because management believes this method results in the most accurate calculation of fair value. Determining the fair value of a reporting unit requires judgment and the use of significant estimates and assumptions, including revenue growth rates, operating margins, discount rates, weighted average costs of capital and future market conditions. 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 quantitative impairment test may indicate a fair value that is substantially similar to the reporting unit’s carrying amount. 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 2017 , a quantitative fair-value based goodwill impairment analysis indicated that the fair value of each of Quanta’s reporting units, with the exception of two reporting units in its Oil and Gas Infrastructure Services Division, was in excess of its carrying amount. Quanta recorded a $57.0 million non-cash charge in the fourth quarter of 2017 for the impairment of goodwill associated with a reporting unit that provides material handling services, which achieved lower operating margins than anticipated during 2017 and is expected to continue to face a highly competitive environment in its select markets, and a reporting unit that provides marine and offshore services, which has experienced prolonged periods of reduced revenues and operating margins and is expected to continue to experience lower levels of activity in the U.S. Gulf of Mexico and other offshore markets. Assuming a 10% decrease in the fair value of each of Quanta’s reporting units, one additional reporting unit within Quanta’s Oil and Gas Infrastructure Services Division would have had a fair value below its carrying amount. Circumstances such as market declines, unfavorable economic conditions, loss of a major customer or other factors could increase the risk of impairment of goodwill for this reporting unit in future periods. If an operating unit experiences prolonged periods of declining revenues, operating margins or both, it may be at risk of failing the quantitative goodwill impairment test. Certain operating units have experienced declines over the short-term due to challenging macroeconomic conditions in certain geographic areas and low oil and natural gas prices, which have negatively impacted customer spending and resulted in project cancellations and delays. Additionally, customer capital spending has been constrained as a result of an increasingly complex regulatory and permitting environment. Certain operating units within Quanta’s Oil and Gas Infrastructure Services Division that primarily operate within the midstream and smaller-scale transmission market, including the reporting units referenced above, have continued to be negatively impacted by these factors. Goodwill and intangible assets associated with these operating units were $48.9 million and $13.1 million at June 30, 2018 . Quanta monitors these conditions and others to determine if it is necessary to perform the quantitative fair-value based impairment test for one or more operating units prior to the annual impairment assessment. No interim impairment charges were recorded during the six months ended June 30, 2018 . Although Quanta is not aware of circumstances that would lead to additional goodwill impairments at this time, circumstances such as a continued market decline, the loss of a major customer or other factors could impact the valuation of goodwill in the future. Other Intangible Assets Quanta’s intangible assets include customer relationships, backlog, trade names, non-compete agreements, patented rights and developed technology and curriculum, all of which are 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 multi-period excess earnings method. This analysis discounts 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 following table presents the significant estimates used by management in determining the fair values of customer relationships associated with acquisitions in the six months ended June 30, 2018 and year ended December 31, 2017 : 2018 2017 Discount rates 25% 17% to 25% Customer attrition rates 20% 15% to 78% Quanta values backlog for acquired businesses as of the acquisition date based upon the contractual nature of the backlog within each service line, discounted to present value. The values of trade names and curriculum are 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 for use of the trade name and curriculum. The value of a non-compete agreement is estimated based on the difference between the present value of the prospective cash flows with it in place and the present value of the prospective cash flows without it in place. Quanta amortizes intangible assets based upon the estimated consumption of their economic benefits, or on a straight-line basis if the pattern of economic benefit cannot otherwise be reliably estimated. Intangible assets subject to amortization are reviewed for impairment and 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 is recognized if the carrying amount of an intangible asset is not recoverable and its carrying amount exceeds its fair value. Intangible asset impairments are included within “Asset impairment charges” in the consolidated statements of operations, when applicable. During the fourth quarter of 2017, Quanta recorded an impairment charge of $1.1 million related to a customer relationship intangible asset, which primarily resulted from a strategic decision to restructure a business within a reporting unit in the Oil and Gas Infrastructure Services Division. |
| Investments in Affiliates and Other Entities | Investments in Affiliates and Other Entities In the normal course of business, Quanta enters into various types of investment arrangements, each having unique terms and conditions. These investments may include equity interests held by Quanta in business entities, including general or limited partnerships, contractual joint ventures, or other forms of equity or profit participation. These investments may also include Quanta’s participation in different financing structures, such as the extension of loans to project-specific entities, the acquisition of convertible notes issued by project specific entities, or other strategic financing arrangements. Quanta also enters into strategic partnerships with customers and infrastructure investors to provide fully integrated infrastructure services on certain projects, including planning and feasibility analyses, engineering, design, procurement, construction and project operation and maintenance. These projects include public-private partnerships and concessions, along with private infrastructure projects such as build, own, operate (and in some cases transfer) and build-to-suit arrangements. As part of this strategy, Quanta formed a partnership with select investors that provides up to $1.0 billion of capital, including approximately $80.0 million from Quanta, available to invest in certain of these infrastructure projects through August 2024. Wholly owned subsidiaries of Quanta serve as the general partner of this partnership and as a separately operated registered investment adviser that manages the invested capital. Quanta determines whether 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 that most significantly affect the VIE’s economic performance and (ii) the obligation to absorb significant losses of or the right to receive significant benefits from, 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 reported as equity in earnings (losses) of unconsolidated affiliates, which is included in “Other income (expense)” in the accompanying condensed consolidated statements of operations. Equity investments are reviewed for impairment by assessing whether any decline in the fair value of the investment below the carrying amount is other than temporary. In making this determination, factors such as the ability to recover the carrying amount of the investment and the inability of the investee to sustain an earnings capacity are evaluated in determining whether a loss in value should be recognized. Any impairment losses related to investments would be recognized in equity in earnings (losses) of unconsolidated affiliates. Equity method investments are carried at original cost adjusted for Quanta’s proportionate share of the investees’ income, losses and distributions and are included in “Other assets, net” in Quanta’s accompanying condensed consolidated balance sheets. Quanta has a minority ownership interest in a limited partnership that was selected during 2014 to build, own and operate a new electric transmission line and two substations in Alberta, Canada. The limited partnership contracted with a Quanta subsidiary to perform the engineering, procurement and construction (EPC) services for the project, and the Quanta subsidiary recognizes revenue and related cost of services as performance progresses on the project. However, due to Quanta’s ownership interest, a proportional amount of the EPC profit is deferred until the electric transmission line and related substations are constructed and ownership of the assets is deemed to be transferred to the third party customer. The profit deferral has been recorded as a decrease to the equity method investment and as a component of equity in earnings (losses) of unconsolidated affiliates, which is included in “Other income (expense)” in the accompanying condensed consolidated statements of operations. Because the profit deferral is greater than the amount invested, the net amount has been included in “Insurance and other non-current liabilities” in the accompanying condensed consolidated balance sheets. See Notes 8 and 10 for additional disclosures related to investments. |
| Revenue Recognition | Revenue Recognition As discussed in Note 3, effective January 1, 2018, Quanta adopted new revenue recognition guidance using the modified retrospective transition method, applying the guidance to contracts with customers that were not substantially complete as of such date. Quanta’s financial results for reporting periods after January 1, 2018 are presented under the new guidance, while financial results for prior periods will continue to be reported in accordance with the prior guidance and Quanta’s historical accounting policy. The net cumulative adjustment due to adoption of the new guidance was a $1.8 million reduction to retained earnings as of January 1, 2018, which primarily related to certain contracts that are now accounted for as a single performance obligation but were previously accounted for separately for revenue recognition purposes. Quanta does not anticipate significant changes to the pattern of revenue recognition for contracts with customers and does not believe that the guidance surrounding the identification of contracts and performance obligations or the measurement of variable consideration will have a material impact on revenue recognition under its customary contractual arrangements. Contracts Quanta designs, installs, upgrades, repairs and maintains infrastructure for customers in the electric power, oil and gas and communications industries. These services may be provided pursuant to master service agreements (MSAs), repair and maintenance contracts and fixed price and non-fixed price installation contracts. These contracts are classified into three categories based on how transaction prices are determined and revenue is recognized: unit-based contracts, cost-plus contracts and fixed price contracts. Transaction prices for unit-based contracts are determined on a per unit basis, transaction prices for cost-plus contracts are determined by applying a profit margin to costs incurred on the contracts and transaction prices for fixed price contracts are determined on a lump-sum basis. All of Quanta’s revenues are recognized from contracts with its customers. In addition to the considerations described below, revenue is not recognized unless collectability under the contract is considered probable, the contract has commercial substance and the contract has been approved. Additionally, the contract must contain payment terms, as well as the rights and commitments of both parties. Performance Obligations A performance obligation is a promise in a contract with a customer to transfer a distinct good or service. Most of Quanta’s contracts are considered to have a single performance obligation whereby Quanta is required to integrate complex activities and equipment into a deliverable for the customer. For contracts with multiple performance obligations, Quanta allocates the transaction price to each performance obligation using its best estimate of the standalone selling price of each distinct good or service in the contract. The standalone selling price is estimated using the expected costs plus a margin approach for each performance obligation. At June 30, 2018 , the aggregate transaction price allocated to unsatisfied or partially satisfied performance obligations was estimated to be approximately $5.58 billion , of which 79.8% was expected to be recognized in the subsequent twelve months. This amount represents management’s estimate of the consolidated revenues that are expected to be realized from the remaining portion of firm orders under fixed price contracts not yet completed or for which work has not yet begun. For purposes of calculating remaining performance obligations, Quanta includes all estimated revenues attributable to consolidated joint ventures and VIEs, revenues from funded and unfunded portions of government contracts to the extent they are reasonably expected to be realized and revenues from change orders and claims to the extent management believes additional contract revenues will be earned and are deemed probable of collection. Excluded from remaining performance obligations were potential orders under MSAs and non-fixed price contracts expected to be completed within one year. Recognition of Revenue Upon Satisfaction of Performance Obligations A transaction price is determined for each contract, and that amount is allocated to each performance obligation within the contract and recognized as revenue when, or as, the performance obligation is satisfied. Quanta generally recognizes revenue over time as it performs its obligations because there is a continuous transfer of control of the deliverable to the customer. Quanta believes that the following methods provide a faithful depiction of when performance obligations under its contracts with customers are satisfied. Under unit-based contracts with an insignificant amount of partially completed units, Quanta recognizes revenue as units are completed based on contractual pricing amounts. Under unit-based contracts with more than an insignificant amount of partially completed units and fixed price contracts, Quanta recognizes revenues as performance obligations are satisfied over time, with the percentage completion generally measured as the percentage of costs incurred to total estimated costs for such performance obligation. Under cost-plus contracts, Quanta recognizes revenue on an input basis, as labor hours are incurred, materials are utilized and services are performed. Contract costs include all direct materials, labor and subcontract costs and indirect costs related to contract performance, such as indirect labor, supplies, tools, repairs and depreciation costs. The majority of the materials associated with Quanta’s work are owner-furnished, and therefore not included in contract revenues and costs. Additionally, Quanta may incur incremental costs to obtain certain contracts, such as selling and marketing costs, bid and proposal costs, sales commissions, and legal fees or initial set-up or mobilization costs, certain of which can be capitalized under the newly adopted revenue recognition guidance. Such costs were not material during the three and six months ended June 30, 2018 . Contract Estimates Actual revenues and project costs can vary, sometimes substantially, from previous estimates due to changes in a variety of factors, including unforeseen or changed circumstances not included in Quanta’s cost estimates or covered by its contracts. The estimating process is based on the professional knowledge and experience of Quanta’s engineers, project managers and financial professionals. Some of the factors that may lead to changes in estimates include concealed or unknown environmental conditions; changes in the cost of equipment, commodities, materials or labor; unanticipated costs or claims due to delays caused by customers or third parties; customer failure to provide required materials or equipment; errors in engineering, specifications or designs; project modifications or contract termination; weather conditions; changes in estimates related to the length of time to complete a performance obligation; and performance and quality issues requiring rework or replacement. These factors, along with other risks inherent in performing services under fixed price contracts, are routinely evaluated by management. Any changes in estimates could result in changes in profitability or losses associated with the related performance obligations. For example, estimated costs for a performance obligation may increase from the original estimate and contractual provisions may not allow for adequate compensation or reimbursement for such additional costs. Changes in estimated revenues, costs and profit are recorded in the period they are determined to be probable and can be reasonably estimated. Changes in estimates on certain contracts may result in the issuance of change orders and/or claims, which may be approved or unapproved by the customer. Quanta determines the probability that such costs will be recovered based on, among other things, contractual entitlement, past practices with the customer, specific discussions or preliminary negotiations with the customer or verbal approvals by the customer. Quanta recognizes amounts associated with change orders and claims as costs of contract performance in the period incurred if it is not probable that the amounts will be recovered or as revenue if it is probable that the contract price will be adjusted and the amount of any such adjustment can be reliably estimated. Most of Quanta’s change orders are for services that are not distinct from an existing contract and are accounted for as part of an existing contract on a cumulative catch-up basis. Quanta accounts for a change order as a separate contract if the additional goods or services are distinct from and increase the scope of, the contract, and the price of the contract increases by an amount commensurate to Quanta’s standalone selling price for the additional goods or services. As of June 30, 2018 and December 31, 2017 , Quanta had recognized revenues of $110.6 million and $144.0 million related to change orders and claims included as contract price adjustments and that were in the process of being negotiated in the normal course of business. These aggregate amounts, which were included in “Contract assets” in the accompanying condensed consolidated balance sheets, represent management’s estimates of additional contract revenues that had been earned and were probable of collection. The amount ultimately realized by Quanta cannot currently be determined but could be significantly higher or lower than the estimated amount. Variable consideration amounts, including performance incentives, early pay discounts and penalties, may also cause changes in contract estimates. The amount of variable consideration is estimated based on the most likely amount that is deemed probable of realization. Contract consideration is adjusted for variable consideration when it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur once the uncertainty related to the variable consideration is resolved. During the three and six months ended June 30, 2018 , revenues were favorably impacted by $15.8 million and $47.4 million as a result of changes in estimates associated with performance obligations on fixed price contracts partially satisfied prior to March 31, 2018 and December 31, 2017 . Quanta’s operating results for the three months ended June 30, 2018 were favorably impacted by $0.8 million , or 0.2% of gross profit, as a result of changes in estimates associated with performance obligations on fixed price contracts partially satisfied prior to March 31, 2018 . Quanta’s operating results for the six months ended June 30, 2018 were favorably impacted by $14.2 million , or 2.2% of gross profit, as a result of changes in estimates associated with performance obligations on fixed price contracts partially satisfied prior to December 31, 2017 . The three and six months ended June 30, 2018 included positive changes of $16.6 million and $26.3 million related to an electric transmission project in Canada, on which Quanta successfully executed through project procurement, winter schedule and productivity risks during the first half of the project, resulting in a decrease of the cost contingency amounts associated with the project. These positive changes were partially offset by negative changes in estimates on other ongoing projects. Quanta’s operating results for the three months ended June 30, 2017 were favorably impacted by $28.8 million , or 9.5% of gross profit, as a result of changes in estimates associated with performance obligations on fixed price contracts partially satisfied prior to March 31, 2017 . The impact for the three months ended June 30, 2017 included $24.6 million of positive changes in estimates on two natural gas pipeline projects that were nearing completion, which primarily related to the favorable mitigation of project risks and the release of related cost contingencies. Quanta’s operating results for the six months ended June 30, 2017 were favorably impacted by $31.0 million , or 5.5% of gross profit, as a result of changes in estimates associated with performance obligations on fixed price contracts partially satisfied prior to December 31, 2016 . Revenues by Category The following tables present Quanta’s revenue disaggregated by geographic location and contract type for the three and six months ended June 30, 2018 (in thousands): Three Months Ended Six Months Ended June 30, 2018 June 30, 2018 By primary geographic location: United States $ 2,193,437 $ 3,905,864 Canada 315,173 853,531 Australia 113,880 233,337 Latin America and Other 33,858 81,192 Total revenues $ 2,656,348 $ 5,073,924 Three Months Ended Six Months Ended June 30, 2018 June 30, 2018 By contract type: Unit-price contracts $ 1,018,145 $ 1,631,583 Fixed price contracts 1,032,991 2,258,080 Cost-plus contracts 605,212 1,184,261 Total revenues $ 2,656,348 $ 5,073,924 Contract Assets and Liabilities With respect to Quanta’s contracts, interim payments are typically received as work progresses in accordance with agreed-upon contractual terms, either at periodic intervals or upon achievement of contractual milestones. As a result, under fixed price contracts the timing of revenue recognition and contract billings results in contract assets and contract liabilities. Contract assets represent revenues recognized in excess of amounts billed for fixed price contracts and are current assets that are transferred to accounts receivable when billed or the billing rights become unconditional. Contract assets are not considered a significant financing component as the intent is to protect the customer in the event Quanta does not perform on its obligations under the contract. Conversely, contract liabilities represent billings in excess of revenues recognized for fixed price contracts. These arise under certain contracts that allow for upfront payments from the customer or contain contractual billing milestones, which result in billings that exceed the amount of revenues recognized for certain periods. Contract liabilities are current liabilities and are not considered a significant financing component, as they are used to meet working capital requirements that are generally higher in the early stages of a contract and protect Quanta from the other party failing to meet its obligations under the contract. Contract assets and liabilities are recorded on a performance obligation basis at the end of each reporting period. Contract assets and liabilities consisted of the following (in thousands): June 30, 2018 December 31, 2017 Contract assets $ 551,505 $ 497,292 Contract liabilities $ 496,083 $ 433,387 The increase in contract assets was primarily due to an increase in revenues for the six months ended June 30, 2018 as compared to the six months ended June 30, 2017 . The increase in contract liabilities was primarily due to an advanced billing position related to the electric transmission project in Canada mentioned above. During the three and six months ended June 30, 2018 , Quanta recognized revenue of approximately $79 million and $343 million related to contract liabilities outstanding at December 31, 2017 . Quanta recognizes unbilled receivables for non-fixed price contracts within “Accounts receivable” in certain circumstances, such as when revenues have been earned and recorded but the amount cannot be billed until a later date, costs have been incurred but are yet to be billed or if amounts arise from routine lags in billing. Quanta also recognizes unearned revenues for non-fixed price contracts when cash is received prior to recognizing revenues for the related performance obligation. Unearned revenues, which are included in “A ccounts payable and accrued expenses, ” were $11.4 million and $16.0 million at June 30, 2018 and December 31, 2017 . Impairment losses recognized on contract assets were not material for the three and six months ended June 30, 2018 . Practical Expedients and Exemptions Quanta utilizes certain practical expedients and exemptions associated with the new revenue recognition guidance. For example, Quanta elected the modified retrospective transition method, which allowed the guidance to be applied only to contracts that were not considered substantially complete as of January 1, 2018. Additionally, in cases where Quanta has a right to consideration from a customer in an amount that corresponds directly with the value of Quanta’s performance completed to date, Quanta recognizes revenue in the amount to which it has a right to invoice and does not disclose such performance as a remaining performance obligation. Also, contract consideration is not adjusted for the effects of a significant financing component if payment is expected to be collected less than one year from when the services are performed. |
| Income Taxes | Income Taxes Quanta follows the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are recorded based on 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, including in connection with changes in tax laws. 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 these reserves, 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 included in the provision for income taxes. As of June 30, 2018 , the total amount of unrecognized tax benefits relating to uncertain tax positions was $35.4 million , a decrease from December 31, 2017 of $0.8 million . This decrease resulted primarily from $2.9 million of payments related to uncertain tax positions for tax years 2012, 2013 and 2014, partially offset by a $2.1 million increase in reserves for uncertain tax positions to be taken for 2018. Although the Internal Revenue Service (IRS) completed its examination of Quanta’s consolidated income tax return for tax years 2010, 2011 and 2012 during the year ended December 31, 2016, Quanta and certain subsidiaries remain under examination by various U.S. state and 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 $13.7 million as a result of settlement of these examinations or as a result of the expiration of certain statute of limitations periods. U.S. federal and state and foreign 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, consolidated statements of operations and consolidated statements of comprehensive income. For example, the Tax Cuts and Jobs Act of 2017 (the Tax Act) significantly revised the U.S. corporate tax regime and resulted in a reduction of Quanta’s future effective tax rate and a remeasurement of its deferred tax assets and liabilities. The Tax Act, among other things, lowered the U.S. federal corporate income tax rate from 35% to 21% effective January 1, 2018, required companies to pay a one-time transition tax on earnings of certain foreign subsidiaries, limited and eliminated certain tax deductions and created new taxes on certain foreign-sourced earnings. Consequently, for the year ended December 31, 2017, Quanta recorded one-time net tax benefits of $70.1 million , including $85.3 million of tax benefits associated with the re-measurement of U.S. federal deferred tax assets and liabilities based on expected future rates (generally 21% ), partially offset by an estimated $15.2 million transition tax on post-1986 earnings and profits of certain foreign subsidiaries. For the year ended December 31, 2017, an additional one-time tax benefit of $26.7 million was recorded in connection with entity restructuring and recapitalization transactions completed by Quanta, which was partially offset by an $8.5 million decrease in the production activity-related tax benefit that resulted from acceleration of certain deductions into 2017. While Quanta has substantially completed its provisional analysis of the effects of the Tax Act and recorded a reasonable estimate of such effects, the net one-time benefits and calculation of income tax expense related to the Tax Act may differ, possibly materially, due to, among other things, further refinement of Quanta’s calculations, changes in interpretations and assumptions made, additional regulatory guidance, and actions and related accounting policy decisions resulting from the Tax Act. For example, the Tax Act imposes a tax on global intangible low-taxed income (GILTI), and it is unclear if GILTI should be included in the period in which it is incurred or whether deferred tax assets and liabilities should be recognized for basis differences expected to reverse as GILTI in future years. Quanta continues to analyze the impacts of the GILTI provision; however, due to the complexity of the new rules, Quanta’s analysis is not yet complete. Accordingly, Quanta has not yet made an accounting policy election related to GILTI. Quanta will complete its analysis of the Tax Act over the one-year measurement period ending December 22, 2018, and any adjustments during the measurement period will be included within “Net income” as an adjustment to “Provision for income taxes” on Quanta’s consolidated statement of operations in the reporting period when such adjustments are determined. |
| Earnings Per Share | Earnings Per Share Basic and diluted earnings per share attributable to common stock are computed using the weighted average number of shares of common stock outstanding during the applicable period. Exchangeable shares that were issued pursuant to certain of Quanta’s historical acquisitions (as further discussed in Note 8), which are exchangeable on a one -for-one basis with shares of Quanta common stock, have been included in the calculation of weighted average shares outstanding for basic and diluted earnings per share attributable to common stock for the portion of the periods that they were outstanding. Additionally, unvested stock-based awards that contain non-forfeitable rights to dividends or dividend equivalents (participating securities) have been included in the calculation of basic and diluted earnings per share attributable to common stock for the portion of the periods that the awards were outstanding. Weighted average shares outstanding for basic and diluted earnings per share attributable to common stock for each of the three and six months ended June 30, 2018 included 2.6 million weighted average participating securities. Weighted average shares outstanding for basic and diluted earnings per share attributable to common stock for the three and six months ended June 30, 2017 included 2.3 million and 2.5 million weighted average participating securities. Diluted earnings per share attributable to common stock is computed using the weighted average number of shares of common stock 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 | Insurance Quanta is insured for employer’s liability, workers’ compensation, auto liability and general liability claims. Under these programs, the deductible for employer’s liability is $1.0 million per occurrence, the deductible for workers’ compensation is $5.0 million per occurrence, and the deductibles for auto liability and general liability are $10.0 million per occurrence. Quanta manages and maintains a portion of its casualty risk through its wholly-owned captive insurance company, which insures all claims up to the amount of the applicable deductible of its third-party insurance programs. 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 $0.5 million per claimant per year. Losses under all of these insurance programs are accrued based upon Quanta’s estimate of the ultimate liability for claims reported and an estimate of claims incurred but not reported, with assistance from third-party actuaries. These insurance liabilities are difficult to assess and estimate due to unknown factors, including the severity of an injury, the extent of damage, the determination of Quanta’s liability in proportion to other parties and the number of incidents not reported. The accruals are based upon known facts and historical trends, and management believes such accruals are adequate. |
| Collective Bargaining Agreements | Collective Bargaining Agreements Some of Quanta’s operating units are parties to various collective bargaining agreements with unions that represent certain of their employees. The collective bargaining agreements expire at various times and have typically been renegotiated and renewed on terms similar to those in the expiring agreements. The agreements require the operating units to pay specified wages, provide certain benefits to their union employees and contribute certain amounts to multiemployer pension plans and employee benefit trusts. Quanta’s multiemployer pension plan contribution rates generally are specified in the collective bargaining agreements (usually on an annual basis), and contributions are made to the plans on a “pay-as-you-go” basis based on its union employee payrolls. The location and number of union employees that Quanta employs at any given time and the plans in which they may participate vary depending on the projects Quanta has ongoing at that time and the need for union resources in connection with those projects. Therefore, Quanta is unable to accurately predict the union employee payroll and the amount of the resulting multiemployer pension plan contribution obligations 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, net of estimated forfeitures. The fair value of these awards is generally determined based on the number of shares or units granted and the closing price of Quanta’s common stock on the date of grant, with the exception of performance units with market-based metrics, the fair value of which is determined using a Monte Carlo simulation valuation methodology. An estimate of future forfeitures, based on historical data, is utilized to determine the period expense. Such estimates are subject to change and may impact the value that will ultimately be recognized as compensation expense. The resulting compensation expense for performance unit and time-based RSU awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period, and the resulting compensation expense for performance-based RSU awards is recognized using the graded vesting method over the requisite service period. The compensation expense related to outstanding performance units can also vary from period to period based on changes in the total number of shares of common stock that Quanta anticipates will be issued upon vesting of such performance units. Payments made by Quanta to satisfy employee tax withholding obligations associated with awards settled in common stock 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 9. |
| 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, Australia and Latin America, is typically the currency of the country where the foreign operating unit is located and transacts the majority of its activities, including billings, financing, payroll and other expenditures. The treatment of foreign currency translation gains or losses is dependent upon management’s determination of the functional currency, and when preparing its consolidated financial statements, Quanta translates the financial statements of its foreign operating units from their functional currency into U.S. dollars. Statements of operations, comprehensive income and cash flows are translated at average monthly rates, while balance sheets are translated at month-end exchange rates. The translation of the balance sheet results in translation gains or losses, which are included as a separate component of equity under “Accumulated other comprehensive income (loss).” Gains and losses arising from transactions not denominated in functional currencies are included within “Other income (expense)” in the accompanying condensed consolidated 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 the likelihood of incurring a loss is probable 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 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). Certain assumptions and other information as they relate to these qualifying assets and liabilities are described below. Contingent Consideration Liabilities. As of June 30, 2018 and December 31, 2017 , financial instruments required to be measured at fair value on a recurring basis consisted primarily of Quanta’s liabilities related to contingent consideration associated with certain acquisitions, the payment of which is contingent upon the future performance of the acquired businesses and, if earned, would be payable to the former owners of the acquired businesses. The liabilities recorded represent the estimated fair values of future amounts payable to the former owners, and the fair values are estimated by management based on entity-specific assumptions that are evaluated on an ongoing basis. As of June 30, 2018 and December 31, 2017 , the aggregate fair value of these outstanding and unearned contingent consideration liabilities totaled $73.0 million and $65.7 million , which was included in “Insurance and other non-current liabilities” in the accompanying condensed consolidated balance sheets. The fair value of contingent consideration liabilities as of June 30, 2018 was primarily determined using a Monte Carlo simulation valuation methodology based on probability-weighted performance projections and other inputs, including a discount rate and an expected volatility factor for each acquisition. The expected volatility factors ranged from 23.0% to 30.0% based on historical asset volatility of selected guideline public companies. Depending on contingent consideration payment terms, the present value of the estimated payments are discounted based on a risk-free rate and/or Quanta’s cost of debt, ranging from 2.1% to 3.4% .The fair value determinations incorporate significant inputs not observable in the market. Accordingly, the level of inputs used for these fair value measurements is the lowest level (Level 3). Significant changes in any of these assumptions could result in a significantly higher or lower potential liability. Quanta expects a significant portion of these liabilities to be settled by late 2020 or early 2021. The majority of Quanta’s contingent consideration liabilities are subject to a maximum payment amount, and the aggregate maximum payout amount for these liabilities was $154.4 million as of June 30, 2018 . One contingent consideration liability is not subject to a maximum payout amount, and the fair value of that liability was $1.0 million as of June 30, 2018 . Quanta’s aggregate contingent consideration liabilities can change due to additional business acquisitions, payments to settle outstanding liabilities, changes in the fair value of amounts owed, and foreign currency translation gains or losses. During the three months ended June 30, 2018 , there were no acquisitions, and during the six months ended June 30, 2018 , one acquisition increased Quanta’s contingent consideration liabilities by $13.7 million . There was no increase to Quanta’s contingent consideration liabilities due to acquisitions during the three and six months ended June 30, 2017. During the three and six months ended June 30, 2018 and 2017, Quanta made no payments related to contingent consideration liabilities. During the three and six months ended June 30, 2018 , there was a $6.3 million decrease in the fair value of contingent consideration liabilities primarily due to changes in forecasted performance for two acquired companies. The change in fair value of contingent consideration liabilities has been reflected in operating income on Quanta’s consolidated statements of operations. Goodwill and Other Intangible Assets. In connection with Quanta’s acquisitions, identifiable intangible assets acquired typically include goodwill, backlog, customer relationships, trade names, covenants not-to-compete, patented rights and developed technology and curriculum. 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 upon the sale of 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, 2017 , 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. Investments and Financial Instruments. Quanta also uses fair value measurements in connection with the valuation of its investments in private company equity interests and financial 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. The level of inputs used for these fair value measurements is the lowest level (Level 3). Other. The carrying amounts of cash equivalents, accounts receivable and accounts payable and accrued expenses approximate fair value due to the short-term nature of these instruments. The carrying amount of variable rate debt also approximates fair value. All of Quanta’s cash equivalents were categorized as Level 1 assets at June 30, 2018 and December 31, 2017 , as all values were based on unadjusted quoted prices for identical assets in an active market that Quanta has the ability to access. Additionally, during the three months ended June 30, 2018 , Quanta recorded a $3.3 million charge associated with the planned exchange of a construction barge for an industrial property, and during the three months ended March 31, 2017, Quanta recorded a $1.9 million charge associated with the planned disposition of the same construction barge, which was not consummated. |
| Adoption of New Accounting Pronouncements | Adoption of New Accounting Pronouncements In May 2014 , the Financial Accounting Standards Board (FASB) issued an update that superseded most revenue recognition guidance, as well as certain cost recognition guidance. The update, together with other clarifying updates, requires that the recognition of revenue related to the transfer of goods or services to customers reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The update also requires additional qualitative and quantitative disclosures about the nature, amount, timing and uncertainty of revenues and cash flows arising from customer contracts, including significant judgments and changes in judgments, and information about contract balances and performance obligations. Quanta adopted the new revenue recognition guidance using the modified retrospective transition method effective January 1, 2018 , applying the guidance to contracts that were not substantially complete as of such date. Quanta’s financial results for reporting periods after January 1, 2018 have been and will be presented under the new guidance, while financial results for prior periods will continue to be reported in accordance with the prior guidance and Quanta’s historical accounting policy. The net cumulative adjustment resulting from adoption was a $1.8 million reduction to retained earnings as of January 1, 2018, which primarily related to certain contracts that are now accounted for as a single performance obligation but were previously accounted for separately for revenue recognition purposes. Quanta has not experienced significant changes to the pattern of revenue recognition for its contracts, the identification of contracts and performance obligations or the measurement of variable consideration. For the three and six months ended June 30, 2018 , the impact related to the adoption of the new revenue recognition guidance on revenues, contract assets and contract liabilities was immaterial. Quanta has also expanded its discussion in Note 2 above to address the quantitative and qualitative disclosure requirements of the new revenue recognition standard. In January 2016 , the FASB issued an update that addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments to provide users of financial statements with more decision-useful information. This update requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. However, an entity may choose to measure equity investments that do not have readily determinable fair values at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. Quanta adopted the new standard effective January 1, 2018 . Quanta’s equity investments that are within the scope of this update do not have readily determinable fair values. Accordingly, Quanta continues to measure these investments at cost less any impairments and also considers changes resulting from any observable price changes as described above. The new standard is not expected to have a material impact on Quanta’s consolidated financial statements in the near-term based on the equity investments held at the time of adoption. In August 2016 , the FASB issued an update intended to standardize the classification of certain transactions on the statements of cash flows . These transactions include contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned life insurance policies and distributions received from equity method investments. The new standard requires application using a retrospective transition method. Quanta adopted this guidance effective January 1, 2018 , and the changes did not have a material impact on its consolidated financial statements. In October 2016 , the FASB issued an update that requires a reporting entity to recognize the tax expense from the sale of an asset in the seller’s tax jurisdiction when the transfer occurs, even though the pre-tax effects of that transaction are eliminated in consolidation. Any deferred tax asset that arises in the buyer’s jurisdiction should be recognized at the time of the transfer. The new guidance does not apply to intra-entity transfers of inventory. The income tax consequences from the sale of inventory from one member of a consolidated entity to another will continue to be deferred until the inventory is sold to a third party. Quanta adopted this guidance effective January 1, 2018 utilizing the modified retrospective method, and the changes did not have a material impact on its consolidated financial statements. In November 2016 , the FASB issued an update intended to standardize the classification of restricted cash and cash equivalents transactions on the statement of cash flows . The new guidance requires net cash withdrawn from (deposited to) restricted cash to be removed from investing activities. Additionally, restricted cash balances for each period are included with “Cash and cash equivalents” in order to obtain beginning and ending balances for condensed consolidated statement of cash flow purposes, and any activity between “Cash and cash equivalents” and restricted cash is no longer reported on Quanta’s consolidated statements of cash flows. Quanta adopted this guidance effective January 1, 2018 utilizing the retrospective transition method, and the changes did not have a material impact on its consolidated financial statements. See Note 12 for reconciliations of “Cash and cash equivalents” and restricted cash. In January 2017 , the FASB issued an update intended to clarify whether transactions should be accounted for as acquisitions or disposals of assets or business es. When substantially all of the fair value of the gross assets acquired or disposed of is concentrated in a single identifiable asset or group of similar identifiable assets, the asset or group is not a business. The update requires, among other things, that to be considered a business, a set of assets and activities must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output. Additionally, the update removes the evaluation of whether a market participant could replace missing elements in order to consider the set of assets and activities a business, provides more stringent criteria for sets without outputs and narrows the definition of output. Quanta adopted this guidance effective January 1, 2018 utilizing the prospective transition method, and the changes did not materially impact its consolidated financial statements. In May 2017 , the FASB issued an update providing guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting. A modification should be accounted for unless the following characteristics of the award are unchanged: the fair value, the vesting conditions and the classification as an equity instrument or a liability instrument. Quanta adopted this guidance effective January 1, 2018 using the prospective transition method, and the changes did not materially impact its consolidated financial statements. Accounting Standards Not Yet Adopted In February 2016 , the FASB issued an update that requires the recognition of operating lease right-of-use assets and the corresponding lease liabilities on the balance sheet. The new standard is effective for interim and annual periods beginning after December 15, 2018. In July 2018, the FASB issued an update that provides entities a choice between the previously required modified retrospective transition method and another transition method that allows entities to initially apply the new standard at the adoption date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. While Quanta continues to evaluate the effect of this standard on its consolidated financial statements, it is anticipated that adoption will result in a significant amount of lease right-of-use assets and corresponding lease liabilities being recorded on its consolidated balance sheets. Quanta has established a cross-functional team to implement this standard and is in the process of evaluating arrangements that will be subject to the standard, is implementing software to meet the reporting and disclosure requirements of the standard and is assessing the impact of the standard on its processes and internal controls. The standard is not expected to have a material impact on Quanta’s compliance with the financial covenants under its senior secured revolving current credit facility. Quanta will adopt this guidance effective January 1, 2019 and will apply the transition method that allows the recognition of a cumulative-effect adjustment to retained earnings on such date. In June 2016 , the FASB issued an update that will change the way companies measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The update will require companies to use an “expected loss” model for instruments measured at amortized cost and to record allowances for available-for-sale debt securities rather than reduce the carrying amounts. The update will also require disclosure of information regarding how a company developed its allowance, including changes in the factors that influenced management’s estimate of expected credit losses and the reasons for those changes. Companies will apply this standard’s provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is effective. The new standard is effective for interim and annual reporting periods beginning after December 15, 2019. Quanta is currently evaluating the potential impact of this authoritative guidance on its consolidated financial statements and will adopt this guidance effective January 1, 2020 . In August 2017 , the FASB issued an update which amends and simplifies existing guidance for presenting the economic effects of risk management activities in the financial statements. The update is effective for interim and annual periods beginning after December 15, 2018. The amended presentation and disclosure guidance is required only prospectively, but certain amendments, if applicable, could require a cumulative-effect adjustment. Quanta is evaluating the impact of this new standard on its consolidated financial statements and will adopt the new standard effective January 1, 2019 ; however, as of June 30, 2018 , Quanta had no hedging relationships outstanding. |
| Segment Reporting | Quanta presents its operations under two reportable segments: (1) Electric Power Infrastructure Services and (2) Oil and Gas Infrastructure Services. This structure is generally based on the broad end-user markets for Quanta’s services. See Note 1 for additional information regarding Quanta’s reportable segments. Quanta’s segment results are derived from the types of services provided across its operating units in each of the end user markets described above. Quanta’s entrepreneurial business model allows each of its operating units to serve the same or similar customers and to provide a range of services across end user markets. Quanta’s operating units are organized into one of two internal divisions, namely, the Electric Power Infrastructure Services Division and the Oil and Gas Infrastructure Services Division. These internal divisions are closely aligned with the reportable segments and are 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 projects for customers in multiple industries, deliver multiple types of services under a single customer contract or provide service offerings to various industries. For example, Quanta performs joint trenching projects to install distribution lines for electric power and natural gas customers. In addition, Quanta’s integrated operations and common administrative support for its operating units require that certain allocations be made to determine segment profitability, including allocations of shared and indirect costs, such as facility costs, indirect operating expenses including depreciation, and general and administrative costs. Certain corporate costs are not allocated and include payroll and benefits, employee travel expenses, facility costs, professional fees, acquisition costs and amortization related to intangible assets. |
| Acquisitions | These allocations require significant use of estimates and is based on information that was available to management at the time these consolidated financial statements were prepared. Quanta uses a variety of information to estimate fair values, including quoted market prices, carrying amounts and valuation techniques such as discounted cash flows. Third-party appraisal firms are engaged to assist in fair value determination of fixed assets, intangible assets and certain other assets and liabilities when appropriate (in thousands). |
