Quarterly report pursuant to Section 13 or 15(d)

Debt Obligations - Narrative (Details)

v3.19.1
Debt Obligations - Narrative (Details)
Oct. 10, 2018
USD ($)
Nov. 20, 2017
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Line of Credit Facility [Line Items]        
Amount borrowed under the credit facility     $ 1,372,050,000 $ 1,070,299,000
Credit facility available for revolving loans or issuing new letters of credit     812,900,000  
Borrowings under Credit Facility | Canadian Dollars        
Line of Credit Facility [Line Items]        
Amount borrowed under the credit facility     123,600,000  
Borrowings under Credit Facility | Australian Dollars        
Line of Credit Facility [Line Items]        
Amount borrowed under the credit facility     36,200,000  
Letters of Credit and Bank Guarantees        
Line of Credit Facility [Line Items]        
Letters of credit and bank guarantees     385,000,000.0  
Letters of Credit and Bank Guarantees | U.S. Dollar        
Line of Credit Facility [Line Items]        
Letters of credit and bank guarantees     240,600,000  
Letters of Credit and Bank Guarantees | Primarily Canadian and Australian Dollars        
Line of Credit Facility [Line Items]        
Letters of credit and bank guarantees     144,400,000  
Senior Secured Credit Facility        
Line of Credit Facility [Line Items]        
Option to increase revolving commitments under the credit agreement $ 400,000,000.0      
Amount borrowed under the credit facility     1,370,000,000  
Reduction in Quanta's funded indebtedness reduced by cash and cash equivalents in excess of this amount   $ 25,000,000.0    
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    
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   $ 100,000,000.0    
Cross default provisions with debt instruments exceeding this amount 150,000,000.0      
Senior Secured Credit Facility | Minimum        
Line of Credit Facility [Line Items]        
Commitment fee   0.20%    
Senior Secured Credit Facility | Maximum        
Line of Credit Facility [Line Items]        
Commitment fee   0.40%    
Senior Secured Credit Facility | 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%    
Senior Secured Credit Facility | 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%    
Senior Secured Credit Facility | Excess of Base Rate Domestic Borrowings Only | Minimum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   0.125%    
Senior Secured Credit Facility | Excess of Base Rate Domestic Borrowings Only | Maximum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   1.00%    
Senior Secured Credit Facility | 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%    
Senior Secured Credit Facility | 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%    
Senior Secured Credit Facility | Excess of Federal Funds Rate        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   0.50%    
Senior Secured Credit Facility | Excess of Euro Currency Rate        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   1.00%    
Senior Secured Credit Facility | Revolving Credit Facility        
Line of Credit Facility [Line Items]        
Borrowing capacity 1,990,000,000      
Amount borrowed under the credit facility     787,100,000  
Senior Secured Credit Facility | Revolving Credit Facility | U.S. Dollar        
Line of Credit Facility [Line Items]        
Amount borrowed under the credit facility     1,210,000,000  
Senior Secured Credit Facility | Term Loan        
Line of Credit Facility [Line Items]        
Borrowing capacity 600,000,000.0      
Amount borrowed under the credit facility     $ 585,000,000.0  
Quarterly amortization payment $ 7,500,000      
Senior Secured Credit Facility | Term Loan | Eurocurrency Rate | Minimum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate 1.125%      
Senior Secured Credit Facility | Term Loan | Eurocurrency Rate | Maximum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate 1.875%      
Senior Secured Credit Facility | Revolving Loans and Letters of Credit in Alternative Currencies        
Line of Credit Facility [Line Items]        
Borrowing capacity $ 600,000,000.0      
Senior Secured Credit Facility | Swing Lines Loan | U.S. Dollar        
Line of Credit Facility [Line Items]        
Borrowing capacity 100,000,000.0      
Senior Secured Credit Facility | Swing Lines Loan | Canadian Dollars        
Line of Credit Facility [Line Items]        
Borrowing capacity 50,000,000.0      
Senior Secured Credit Facility | Swing Lines Loan | Australian Dollars        
Line of Credit Facility [Line Items]        
Borrowing capacity $ 50,000,000.0      
Senior Secured Credit Facility | Standby Letters of Credit | Minimum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   1.125%    
Senior Secured Credit Facility | Standby Letters of Credit | Maximum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   2.00%    
Senior Secured Credit Facility | Performance Letters of Credit | Minimum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   0.675%    
Senior Secured Credit Facility | Performance Letters of Credit | Maximum        
Line of Credit Facility [Line Items]        
Debt instrument basis spread on variable rate   1.15%