New Accounting Pronouncements	12 Months Ended
Dec. 31, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS: Adoption of New Accounting Pronouncements In July 2015, the FASB issued an update that requires inventory to be measured at the lower of either cost or net realizable value. When evidence exists that the net realizable value of inventory is lower than its cost, the difference will be recognized as a loss in earnings in the period in which it occurs. Quanta adopted this guidance effective January 1, 2017, and the adoption of the update did not have a significant impact on its consolidated financial statements or related disclosures. In March 2016, the FASB issued an update that amends the accounting for share-based payments in several key areas, including the treatment and cash flow presentation of tax effects related to the settlement of share-based payments and the accounting for forfeitures of share-based awards. The new guidance requires companies with share-based payments to record all related tax effects at settlement (or expiration) through income tax expense on the statement of operations rather than through additional paid-in capital (APIC) within equity. This update also requires excess tax benefits to be classified as an operating activity on the statement of cash flows rather than classified as a financing activity and requires cash paid by an employer when withholding shares for the employee portion of taxes to be presented as a financing activity. The update also allows companies to either account for forfeitures of share-based payments as they occur or to estimate forfeitures. This guidance is required to be applied prospectively except for the classification of cash related to tax withholding, which requires retrospective application. Quanta adopted this guidance effective January 1, 2017 and will continue to estimate forfeitures of share-based payments. Quanta experienced increased volatility of income tax expense after adoption of this guidance and anticipates that trend to continue. During the year ended December 31, 2017, Quanta recorded income tax benefits of $5.1 million related to the settlement of share-based awards. APIC was not adjusted for amounts recorded prior to 2017, and therefore Quanta’s retained earnings were not affected by the adoption of this guidance. Additionally, $8.3 million and $9.8 million were reclassified from operating activities to financing activities on the statements of cash flows for the years ended December 31, 2016 and 2015 associated with cash paid by Quanta to satisfy tax withholding obligations for share-settled awards. Further, the presentation of excess tax benefits on the statements of cash flows is now shown as cash flows from operating activities rather than in financing activities. The excess tax benefits reclassified to operating activities for each of the years ended December 31, 2016 and 2015 was $0.7 million. In October 2016, the FASB issued an update that amends the consolidation guidance related to how a reporting entity that is the single decision maker of a VIE should treat indirect interests in the VIE held through related parties that are under common control with the reporting entity when determining whether it is the primary beneficiary of a VIE. A reporting entity has an indirect interest in a VIE if it has a direct interest in a related party that, in turn, has a direct interest in the VIE. Quanta adopted this guidance effective January 1, 2017, and the adoption of the update did not have a significant impact on its consolidated financial statements or related disclosures. In January 2017, the FASB issued an update intended to simplify the subsequent measurement of goodwill by eliminating the second step in the two-step goodwill impairment test. As permitted under this guidance, Quanta elected to adopt this guidance for its annual goodwill impairment test during the fourth quarter of 2017 (see Note 2 for further detail on this update and a description of the quantitative goodwill impairment test). Accounting Standards Not Yet Adopted To be adopted effective January 1, 2018: In May 2014, the FASB issued an update that supersedes most current 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 new qualitative and quantitative disclosures about the nature, amount, timing and uncertainty of revenues and cash flows arising from customer contracts, including significant judgments and changes in judgments, information about contract balances and performance obligations, and assets recognized from costs incurred to obtain or fulfill a contract. The new guidance is effective for fiscal years beginning on or after December 15, 2017 and 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 will adopt the new revenue recognition guidance using the modified retrospective transition method effective for the quarter ending March 31, 2018, applying the guidance to contracts that were not substantially complete as of January 1, 2018. Quanta’s financial results for reporting periods after January 1, 2018 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. Quanta has substantially completed its evaluation of the impact of the new guidance on its contracts with customers, including identification of differences that will result from the new requirements. Based on this evaluation, we estimate that the net cumulative adjustment to retained earnings from adoption as of January 1, 2018, will be less than $10.0 million. With respect to ongoing revenues generated from master service agreements, repair and maintenance contracts and fixed price and non-fixed price installation contracts, Quanta does not anticipate any significant changes to the pattern of revenue recognition and does not believe that the guidance surrounding identification of contracts and performance obligations or measurement of variable consideration will have a material impact on the revenue recognition for these arrangements. Quanta expects its disclosures related to revenue recognition will expand to address new quantitative and qualitative requirements regarding the nature, amount and timing of revenue from contracts and additional information related to contract assets and liabilities. 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. The new standard is effective for interim and annual periods beginning after December 15, 2017, and Quanta will adopt 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 intends to continue to measure these investments at cost less any impairments and will also consider 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 it held as of December 31, 2017. 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 is effective for interim and annual reporting periods beginning after December 15, 2017 and requires application using a retrospective transition method. Quanta will adopt this guidance effective January 1, 2018 and does not expect it to have a material impact on its consolidated financial statements. In October 2016, the FASB issued an update that will require 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 would also be recognized at the time of the transfer. The new guidance will 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. The new standard is effective for interim and annual reporting periods beginning after December 15, 2017. The modified retrospective method will be required for transition to the new guidance, with a cumulative-effect adjustment recorded in retained earnings as of the beginning of the period of adoption, if applicable. Quanta will adopt this guidance effective January 1, 2018 and does not expect it to 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 of continuing operations. Additionally, restricted cash balances for each period will be included with “Cash and cash equivalents” in order to obtain beginning and ending balances for consolidated statement of cash flow purposes, and any activity between “Cash and cash equivalents” and restricted cash will no longer be reported on Quanta’s consolidated statements of cash flows. The new standard is effective for interim and annual reporting periods beginning after December 15, 2017. The retrospective transition method will be required for this new guidance. Quanta will adopt this guidance effective January 1, 2018 and does not expect it to have a material impact on its consolidated financial statements. In January 2017, the FASB issued an update intended to clarify whether transactions should be accounted for as acquisitions or disposals of assets or businesses. 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 will require, 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. The update is effective for interim and annual reporting periods beginning after December 15, 2017, and the prospective transition method will be required for this new guidance. Accordingly, Quanta will adopt this guidance effective January 1, 2018 and does not expect it to impact its consolidated financial statements prior to such date. 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. The update is effective for interim and annual periods beginning after December 15, 2017 and is required to be applied prospectively. Accordingly, Quanta will adopt this guidance effective January 1, 2018 and does not expect it to impact its consolidated financial statements prior to such date. To be adopted subsequent to January 1, 2018: In February 2016, the FASB issued an update that requires companies to recognize on the balance sheet the contractual right to use assets and liabilities corresponding to the rights and obligations created by lease contracts. The new standard is effective for interim and annual periods beginning after December 15, 2018. While Quanta continues to evaluate the effect of the standard on its consolidated financial statements, it is anticipated that the adoption of the standard will materially impact its consolidated balance sheets. Quanta will adopt this guidance by January 1, 2019. 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 by 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 by January 1, 2019; however, as of December 31, 2017, Quanta had no hedging relationships outstanding.

NEW ACCOUNTING PRONOUNCEMENTS:

Adoption of New Accounting Pronouncements

In July 2015, the FASB issued an update that requires inventory to be measured at the lower of either cost or net realizable value. When evidence exists that the net realizable value of inventory is lower than its cost, the difference will be recognized as a loss in earnings in the period in which it occurs. Quanta adopted this guidance effective January 1, 2017, and the adoption of the update did not have a significant impact on its consolidated financial statements or related disclosures.

In March 2016, the FASB issued an update that amends the accounting for share-based payments in several key areas, including the treatment and cash flow presentation of tax effects related to the settlement of share-based payments and the accounting for forfeitures of share-based awards. The new guidance requires companies with share-based payments to record all related tax effects at settlement (or expiration) through income tax expense on the statement of operations rather than through additional paid-in capital (APIC) within equity. This update also requires excess tax benefits to be classified as an operating activity on the statement of cash flows rather than classified as a financing activity and requires cash paid by an employer when withholding shares for the employee portion of taxes to be presented as a financing activity. The update also allows companies to either account for forfeitures of share-based payments as they occur or to estimate forfeitures. This guidance is required to be applied prospectively except for the classification of cash related to tax withholding, which requires retrospective application. Quanta adopted this guidance effective January 1, 2017 and will continue to estimate forfeitures of share-based payments. Quanta experienced increased volatility of income tax expense after adoption of this guidance and anticipates that trend to continue. During the year ended December 31, 2017, Quanta recorded income tax benefits of $5.1 million related to the settlement of share-based awards. APIC was not adjusted for amounts recorded prior to 2017, and therefore Quanta’s retained earnings were not affected by the adoption of this guidance. Additionally, $8.3 million and $9.8 million were reclassified from operating activities to financing activities on the statements of cash flows for the years ended December 31, 2016 and 2015 associated with cash paid by Quanta to satisfy tax withholding obligations for share-settled awards. Further, the presentation of excess tax benefits on the statements of cash flows is now shown as cash flows from operating activities rather than in financing activities. The excess tax benefits reclassified to operating activities for each of the years ended December 31, 2016 and 2015 was $0.7 million.

In October 2016, the FASB issued an update that amends the consolidation guidance related to how a reporting entity that is the single decision maker of a VIE should treat indirect interests in the VIE held through related parties that are under common control with the reporting entity when determining whether it is the primary beneficiary of a VIE. A reporting entity has an indirect interest in a VIE if it has a direct interest in a related party that, in turn, has a direct interest in the VIE. Quanta adopted this guidance effective January 1, 2017, and the adoption of the update did not have a significant impact on its consolidated financial statements or related disclosures.

In January 2017, the FASB issued an update intended to simplify the subsequent measurement of goodwill by eliminating the second step in the two-step goodwill impairment test. As permitted under this guidance, Quanta elected to adopt this guidance for its annual goodwill impairment test during the fourth quarter of 2017 (see Note 2 for further detail on this update and a description of the quantitative goodwill impairment test).

Accounting Standards Not Yet Adopted

To be adopted effective January 1, 2018:

In May 2014, the FASB issued an update that supersedes most current 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 new qualitative and quantitative disclosures about the nature, amount, timing and uncertainty of revenues and cash flows arising from customer contracts, including significant judgments and changes in judgments, information about contract balances and performance obligations, and assets recognized from costs incurred to obtain or fulfill a contract. The new guidance is effective for fiscal years beginning on or after December 15, 2017 and 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 will adopt the new revenue recognition guidance using the modified retrospective transition method effective for the quarter ending March 31, 2018, applying the guidance to contracts that were not substantially complete as of January 1, 2018. Quanta’s financial results for reporting periods after January 1, 2018 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. Quanta has substantially completed its evaluation of the impact of the new guidance on its contracts with customers, including identification of differences that will result from the new requirements. Based on this evaluation, we estimate that the net cumulative adjustment to retained earnings from adoption as of January 1, 2018, will be less than $10.0 million. With respect to ongoing revenues generated from master service agreements, repair and maintenance contracts and fixed price and non-fixed price installation contracts, Quanta does not anticipate any significant changes to the pattern of revenue recognition and does not believe that the guidance surrounding identification of contracts and performance obligations or measurement of variable consideration will have a material impact on the revenue recognition for these arrangements. Quanta expects its disclosures related to revenue recognition will expand to address new quantitative and qualitative requirements regarding the nature, amount and timing of revenue from contracts and additional information related to contract assets and liabilities.

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. The new standard is effective for interim and annual periods beginning after December 15, 2017, and Quanta will adopt 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 intends to continue to measure these investments at cost less any impairments and will also consider 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 it held as of December 31, 2017.

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 is effective for interim and annual reporting periods beginning after December 15, 2017 and requires application using a retrospective transition method. Quanta will adopt this guidance effective January 1, 2018 and does not expect it to have a material impact on its consolidated financial statements.

In October 2016, the FASB issued an update that will require 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 would also be recognized at the time of the transfer. The new guidance will 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. The new standard is effective for interim and annual reporting periods beginning after December 15, 2017. The modified retrospective method will be required for transition to the new guidance, with a cumulative-effect adjustment recorded in retained earnings as of the beginning of the period of adoption, if applicable. Quanta will adopt this guidance effective January 1, 2018 and does not expect it to 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 of continuing operations. Additionally, restricted cash balances for each period will be included with “Cash and cash equivalents” in order to obtain beginning and ending balances for consolidated statement of cash flow purposes, and any activity between “Cash and cash equivalents” and restricted cash will no longer be reported on Quanta’s consolidated statements of cash flows. The new standard is effective for interim and annual reporting periods beginning after December 15, 2017. The retrospective transition method will be required for this new guidance. Quanta will adopt this guidance effective January 1, 2018 and does not expect it to have a material impact on its consolidated financial statements.

In January 2017, the FASB issued an update intended to clarify whether transactions should be accounted for as acquisitions or disposals of assets or businesses. 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 will require, 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. The update is effective for interim and annual reporting periods beginning after December 15, 2017, and the prospective transition method will be required for this new guidance. Accordingly, Quanta will adopt this guidance effective January 1, 2018 and does not expect it to impact its consolidated financial statements prior to such date.

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. The update is effective for interim and annual periods beginning after December 15, 2017 and is required to be applied prospectively. Accordingly, Quanta will adopt this guidance effective January 1, 2018 and does not expect it to impact its consolidated financial statements prior to such date.

To be adopted subsequent to January 1, 2018:

In February 2016, the FASB issued an update that requires companies to recognize on the balance sheet the contractual right to use assets and liabilities corresponding to the rights and obligations created by lease contracts. The new standard is effective for interim and annual periods beginning after December 15, 2018. While Quanta continues to evaluate the effect of the standard on its consolidated financial statements, it is anticipated that the adoption of the standard will materially impact its consolidated balance sheets. Quanta will adopt this guidance by January 1, 2019.

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 by 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 by January 1, 2019; however, as of December 31, 2017, Quanta had no hedging relationships outstanding.