Quarterly report pursuant to Section 13 or 15(d)

Debt Obligations - Credit Facility Terms under the Amended and Restated Credit Agreement (Detail)

v3.7.0.1
Debt Obligations - Credit Facility Terms under the Amended and Restated Credit Agreement (Detail) - Current Credit Agreement
6 Months Ended
Jun. 30, 2017
USD ($)
Line of Credit Facility [Line Items]  
Reduction in Quanta's funded indebtedness reduced by cash and cash equivalents in excess of this amount $ 25,000,000.0
Percentage of capital stock of direct foreign subsidiaries of wholly owned U.S. subsidiaries to secure credit agreement 65.00%
Amount of availability under the credit agreement and/or cash and cash equivalents on hand that must be present to allow for cash payments of dividends and stock repurchases $ 100,000,000
Cross default provisions with debt instruments exceeding this amount $ 100,000,000
Minimum  
Line of Credit Facility [Line Items]  
Commitment fee 0.20%
Minimum | Standby Letters of Credit  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 1.125%
Minimum | Performance Letters of Credit  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 0.675%
Maximum  
Line of Credit Facility [Line Items]  
Commitment fee 0.40%
Maximum | Standby Letters of Credit  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 2.125%
Maximum | Performance Letters of Credit  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 1.275%
Excess of Eurocurrency Rate Applicable to Domestic Borrowings Only | Minimum  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 1.125%
Excess of Eurocurrency Rate Applicable to Domestic Borrowings Only | Maximum  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 2.125%
Excess of Base Rate Domestic Borrowings Only | Minimum  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 0.125%
Excess of Base Rate Domestic Borrowings Only | Maximum  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 1.125%
Excess of Euro Currency Rate of Credit Agreement for Foreign Borrowings | Minimum  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 1.125%
Excess of Euro Currency Rate of Credit Agreement for Foreign Borrowings | Maximum  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 2.125%
Excess of Federal Funds Rate  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 0.50%
Excess of Euro Currency Rate  
Line of Credit Facility [Line Items]  
Debt instrument basis spread on variable rate 1.00%