Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements (Summary of Financial Instruments at Carrying and Fair Value) (Details)

v3.20.2
Fair Value Measurements (Summary of Financial Instruments at Carrying and Fair Value) (Details) - USD ($)
$ in Thousands
Sep. 30, 2020
Dec. 31, 2019
Oct. 03, 2016
6.25% Senior Notes due 2023      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Debt instrument, interest rate, stated (as a percent)     6.25%
6.125% Senior Notes due 2024      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Debt instrument, interest rate, stated (as a percent)     6.125%
9.00% Second Lien Senior Secured Notes due 2025      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Debt instrument, interest rate, stated (as a percent) 9.00%    
Unsecured debt | 6.25% Senior Notes due 2023      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Debt instrument, interest rate, stated (as a percent) 6.25%   6.25%
Unsecured debt | 6.125% Senior Notes due 2024      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Debt instrument, interest rate, stated (as a percent) 6.125%    
Unsecured debt | 8.25% Senior Notes due 2025      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Debt instrument, interest rate, stated (as a percent) 8.25%    
Unsecured debt | 6.375% Senior Unsecured Notes due 2026      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Debt instrument, interest rate, stated (as a percent) 6.375%    
Carrying Value | Level 2      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Total $ 1,900,000 $ 1,900,000  
Carrying Value | Level 2 | Unsecured debt | 6.25% Senior Notes due 2023      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 650,000 650,000  
Carrying Value | Level 2 | Unsecured debt | 6.125% Senior Notes due 2024      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 600,000 600,000  
Carrying Value | Level 2 | Unsecured debt | 8.25% Senior Notes due 2025      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 250,000 250,000  
Carrying Value | Level 2 | Unsecured debt | 6.375% Senior Unsecured Notes due 2026      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 400,000 400,000  
Carrying Value | Level 3 | 9.00% Second Lien Senior Secured Notes due 2025      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Total 300,000 0  
Fair Value | Level 2      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Total 745,500 1,930,929  
Fair Value | Level 2 | Unsecured debt | 6.25% Senior Notes due 2023      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 273,000 658,125  
Fair Value | Level 2 | Unsecured debt | 6.125% Senior Notes due 2024      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 240,000 611,130  
Fair Value | Level 2 | Unsecured debt | 8.25% Senior Notes due 2025      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 92,500 256,250  
Fair Value | Level 2 | Unsecured debt | 6.375% Senior Unsecured Notes due 2026      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Senior Notes 140,000 405,424  
Fair Value | Level 3 | 9.00% Second Lien Senior Secured Notes due 2025      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Total $ 260,966 $ 0