Annual report pursuant to Section 13 and 15(d)

Long-term Debt - Notes (Details)

v3.8.0.1
Long-term Debt - Notes (Details) - USD ($)
 12 Months Ended
Dec. 11, 2017
Oct. 03, 2017
May 04, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Debt Instrument [Line Items]              
Long term debt outstanding       $ 2,270,279,000 $ 2,617,970,000    
Unamortized deferred financing costs       21,403,000 27,275,000    
Original issue discount       18,390,000 28,497,000    
Repayments of long-term debt       $ 739,472,000 479,059,000 $ 5,000,000  
Senior Notes | 6.75% Senior Secured Notes due 2022              
Debt Instrument [Line Items]              
Debt instrument face amount     $ 625,000,000        
Debt instrument stated interest rate     6.75% 6.75%      
Long term debt outstanding       $ 625,000,000 625,000,000    
Senior Notes | 8.5% Senior Notes due 2022              
Debt Instrument [Line Items]              
Debt instrument face amount             $ 200,000,000
Debt instrument stated interest rate       8.50%     8.50%
Redemption premium paid $ 8,500,000            
Debt instrument issued, percentage of principal             100.00%
Long term debt outstanding     $ 200,000,000 $ 0 200,000,000    
Debt extinguishment costs 7,996,000            
Unamortized deferred financing costs 5,207,000            
Interest expense, debt             $ 3,000,000
Repayments of long-term debt 200,000,000            
Unsecured Debt | Floating Rate Senior Unsecured Notes due 2022              
Debt Instrument [Line Items]              
Debt instrument face amount   $ 525,000,000 $ 525,000,000        
Redemption premium paid 7,091,000            
Debt instrument issued, percentage of principal     98.00%        
Long term debt outstanding   78,792,000   0 525,000,000    
Debt extinguishment amount 78,792,000 446,208,000          
Debt extinguishment costs 6,043,000 32,284,000   $ 47,875,000 0    
Unamortized deferred financing costs 108,000 696,000          
Original issue discount 1,176,000 $ 7,555,000          
Unsecured Debt | Floating Rate Senior Unsecured Notes due 2022 | LIBOR              
Debt Instrument [Line Items]              
Variable rate on spread     10.75%        
Debt instrument, interest rate floor     1.00%        
Unsecured Debt | 5.75% Senior Unsecured Notes due 2025              
Debt Instrument [Line Items]              
Debt instrument face amount $ 300,000,000            
Debt instrument stated interest rate 5.75%     5.75%      
Debt instrument, redemption price percentage 105.75%     100.00%      
Long term debt outstanding       $ 300,000,000 $ 0    
Debt instrument, call premium       1.00%      
Unsecured Debt | 5.75% Senior Unsecured Notes due 2025 | U.S. Treasury              
Debt Instrument [Line Items]              
Variable rate on spread 5.00%            
Change of Control | Senior Notes | 6.75% Senior Secured Notes due 2022              
Debt Instrument [Line Items]              
Debt instrument, redemption price percentage       101.00%      
Change of Control | Unsecured Debt | 5.75% Senior Unsecured Notes due 2025              
Debt Instrument [Line Items]              
Debt instrument, redemption price percentage       101.00%      
Minimum | Event of Default | Unsecured Debt | 5.75% Senior Unsecured Notes due 2025              
Debt Instrument [Line Items]              
Potential percentage of principal redeemed       30.00%      
Maximum | Exercise of Call Option | Unsecured Debt | 5.75% Senior Unsecured Notes due 2025              
Debt Instrument [Line Items]              
Potential percentage of principal redeemed       40.00%