Quarterly report pursuant to Section 13 or 15(d)

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

v3.10.0.1
Debt Obligations - Credit Facility Terms under the Amended and Restated Credit Agreement (Detail) - Current Credit Agreement
23 Months Ended
Nov. 20, 2017
USD ($)
Nov. 19, 2017
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%  
Maximum consolidated leverage ratio 3.0  
Acquisition threshold for leverage ratio $ 200,000,000.0  
Maximum leverage ratio acquisition completed in current and two subsequent quarters 3.5  
Minimum consolidated interest coverage ratio 3.0  
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 $ 100,000,000.0  
Cross default provisions with debt instruments exceeding this amount $ 100,000,000.0  
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% 1.125%
Minimum | Performance Letters of Credit    
Line of Credit Facility [Line Items]    
Debt instrument basis spread on variable rate 0.675% 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 2.00% 2.125%
Maximum | Performance Letters of Credit    
Line of Credit Facility [Line Items]    
Debt instrument basis spread on variable rate 1.15% 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% 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 2.00% 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% 0.125%
Excess of Base Rate Domestic Borrowings Only | Maximum    
Line of Credit Facility [Line Items]    
Debt instrument basis spread on variable rate 1.00% 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% 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 2.00% 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%