XML 55 R45.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Summary of Significant Accounting Policies - Stock-Based Compensation (Detail) | 9 Months Ended
--- | ---
Sep. 30, 2018 shares
Restricted Stock Units to be Settled in Cash |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Amount in cash received for each RSU is equal to the fair value of this number of Quanta common stock shares (in shares) | 1

X
- Definition Amount in cash received for each RSU is equal to the fair value of this number of Quanta common stock shares. + References No definition available. + Details
Name: | pwr_AmountInCashReceivedForEachRSUIsEqualToFairValueOfThisNumberOfQuantaCommonStockShares
Namespace Prefix: | pwr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=pwr_RestrictedStockUnitsToBeSettledInCashMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |