Annual report pursuant to Section 13 and 15(d)

Long-Term Debt - Additional Information (Details)

v3.19.3.a.u2
Long-Term Debt - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Nov. 25, 2019
Jul. 31, 2019
Debt Instrument [Line Items]          
Long-tern debt $ 2,002,402,000        
Deferred finance costs 23,751,000 $ 30,733,000      
Authorized amount         $ 100,000,000
Repurchased face amount 200,000,000        
Capitalized interest (3,372,000) (4,470,000) $ (9,470,000)    
Gain on extinguishment of debt 48,630,000 0 0    
Revolving credit facility          
Debt Instrument [Line Items]          
Debt instrument, repurchase amount 138,800,000        
Repurchased face amount 190,100,000        
Gain on extinguishment of debt 48,600,000        
Oil and gas properties          
Debt Instrument [Line Items]          
Capitalized interest $ (3,400,000) (4,500,000) $ (9,500,000)    
Nova Scotia, Amegy, KeyBank | Revolving credit agreement          
Debt Instrument [Line Items]          
Weight average interest rate 3.30%        
InterBank | Letter of credit | Construction loans          
Debt Instrument [Line Items]          
Deferred finance costs $ 100,000        
Debt issued 22,453,000 23,149,000      
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Revolving credit agreement          
Debt Instrument [Line Items]          
Maximum borrowing capacity 1,400,000,000        
Borrowing base 1,000,000,000.0     $ 1,200,000,000  
Debt issued 120,000,000.0 $ 45,000,000      
Amended and Restated Credit Agreement | Nova Scotia, Amegy, KeyBank | Letter of credit          
Debt Instrument [Line Items]          
Long-term line of credit outstanding 243,600,000        
Future borrowings available $ 636,400,000        
6.625% Senior Notes Due 2023 | Senior notes          
Debt Instrument [Line Items]          
Stated interest rate 6.625% 6.625% 6.625%    
Deferred finance costs $ 3,300,000        
Repurchased face amount 20,500,000        
Debt issued $ 329,467,000 $ 350,000,000      
6.000% Senior Notes Due 2024 | Senior notes          
Debt Instrument [Line Items]          
Stated interest rate 6.00% 6.00% 6.00%    
Deferred finance costs $ 6,900,000        
Repurchased face amount 46,600,000        
Debt issued $ 603,428,000 $ 650,000,000      
6.375% Senior Notes Due 2025 | Senior notes          
Debt Instrument [Line Items]          
Stated interest rate 6.375% 6.375% 6.375%    
Deferred finance costs $ 9,600,000        
Debt issued $ 529,525,000 $ 600,000,000      
6.375% Senior Notes Due 2026 | Senior notes          
Debt Instrument [Line Items]          
Stated interest rate 6.375% 6.375% 6.375%    
Deferred finance costs $ 3,900,000        
Repurchased face amount 52,500,000        
Debt issued 397,529,000 $ 450,000,000      
6.375% Senior Notes | Senior notes          
Debt Instrument [Line Items]          
Repurchased face amount 70,500,000        
Carrying value | Senior notes          
Debt Instrument [Line Items]          
Outstanding debt 1,800,000,000        
Fair value | Senior notes          
Debt Instrument [Line Items]          
Outstanding debt $ 1,300,000,000