XML 52 R38.htm IDEA: XBRL DOCUMENT v3.20.2
Long-term debt - Narrative (Details)
Jun. 11, 2020
Jun. 10, 2020
Feb. 11, 2020
USD ($)
Jun. 30, 2020
USD ($)
Jan. 09, 2020
USD ($)
Dec. 31, 2019
USD ($)
Debt Instrument [Line Items]            
Early redemption fees     $ 13,800,000      
Write off of unamortized financing fees and discounts     7,900,000      
Cash and cash equivalents       $ 173,070,000   $ 29,404,000
Senior Notes Bearing Interest at 4.625 Percent Due March 2028            
Debt Instrument [Line Items]            
Stated interest rate (as a percent)         4.625%  
Senior Notes Bearing Interest at 4.625 Percent Due March 2028 | Senior Notes            
Debt Instrument [Line Items]            
Principal amount of unsecured notes     $ 1,000,000,000.0   $ 1,000,000,000.0  
Unsecured notes bearing fixed rate interest at 5.125% due July 2020            
Debt Instrument [Line Items]            
Stated interest rate (as a percent)     5.125% 5.125%    
Repayments of unsecured debt     $ 310,000,000.0      
Unsecured notes bearing fixed rate interest at 6.375% due October 2023            
Debt Instrument [Line Items]            
Stated interest rate (as a percent)     6.375% 6.375%    
Repayments of unsecured debt     $ 650,000,000.0      
Borrowings under revolving credit agreement expiring August 2024            
Debt Instrument [Line Items]            
Maximum leverage ratio 5.25 5.50        
Amended and Restated Competitive Advance and Revolving Credit Agreement | Line of Credit | Revolving Credit Facility            
Debt Instrument [Line Items]            
Unused borrowing capacity       $ 653,800,000    
Maximum borrowing capacity under credit facility       $ 1,510,000,000