Annual report pursuant to Section 13 and 15(d)

Borrowings (Senior Unsecured Notes Exchange) (Details)

v3.20.4
Borrowings (Senior Unsecured Notes Exchange) (Details) - USD ($)
$ / shares in Units, shares in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Nov. 30, 2020
Nov. 02, 2020
Sep. 30, 2020
May 07, 2020
Dec. 20, 2019
Aug. 31, 2018
Jun. 07, 2018
Oct. 03, 2016
Debt Instrument, Redemption [Line Items]                      
(Gain) loss on extinguishment of debt $ (170,370,000) $ 4,881,000 $ 0                
Warrants outstanding       1,750              
Exercise price of warrants (in usd per share)           $ 5.60          
Unsecured debt                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument principal amount         $ 389,000,000.0            
Debt instrument aggregate principal amount         389,000,000.0            
6.25% Senior Notes due 2023                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument, interest rate, stated (as a percent) 6.25%             6.25%     6.25%
6.125% Senior Notes due 2024                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument, interest rate, stated (as a percent) 6.125%                   6.125%
8.25% Senior Notes due 2025                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument, interest rate, stated (as a percent) 8.25%             8.25%      
6.375% Senior Notes due 2026                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument, interest rate, stated (as a percent) 6.375%                    
6.375% Senior Notes due 2026 | Unsecured debt                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument, interest rate, stated (as a percent)                 6.375% 6.375%  
Debt instrument principal amount                   $ 400,000,000.0  
Debt instrument aggregate principal amount                   $ 400,000,000.0  
9.00% Second Lien Notes                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument, interest rate, stated (as a percent) 9.00%         9.00%          
Debt instrument principal amount $ 300,000,000.0         $ 300,000,000.0 $ 400,000,000.0        
Exchange ratio         557            
Debt instrument aggregate principal amount 300,000,000.0         $ 300,000,000.0 $ 400,000,000.0        
9.00% Second Lien Notes | Unsecured debt                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument principal amount 207,600,000       216,700,000            
Debt instrument aggregate principal amount $ 207,600,000       $ 216,700,000            
November 2020 Warrants                      
Debt Instrument, Redemption [Line Items]                      
Warrants outstanding 1,750                    
Debt instrument, term 5 years                    
November 2020 Warrants | Unsecured debt                      
Debt Instrument, Redemption [Line Items]                      
Debt instrument principal amount $ 9,100,000                    
Debt instrument aggregate principal amount 9,100,000                    
Debt instrument, discount $ 9,100,000