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Long-Term Debt - Narrative (Details) - USD ($)
1 Months Ended 12 Months Ended
Jun. 21, 2019
Jun. 20, 2019
Feb. 28, 2018
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Nov. 30, 2019
Oct. 31, 2018
Sep. 30, 2018
Debt Instrument [Line Items]                  
Face value of long-term debt       $ 57,500,000 $ 0        
Repayments of long-term debt       153,596,000 46,304,000 $ 0      
Gain on extinguishment of debt       0 1,151,000 $ 0      
Revolving Credit Facility                  
Debt Instrument [Line Items]                  
Face value of long-term debt       57,500,000 0        
Credit Facility [Member] | Revolving Credit Facility                  
Debt Instrument [Line Items]                  
Maximum borrowing capacity $ 600,000,000.0           $ 225,000,000.0    
Line of credit facility, current borrowing capacity $ 300,000,000.0             $ 350,000,000.0 $ 425,000,000.0
Face value of long-term debt       57,500,000          
Letters of credit outstanding       $ 2,900,000          
Line of credit facility, unused capacity, commitment fee percentage       0.50%          
Interest rate during period       4.70%          
Minimum collateral amount of proved oil and gas reserves representing the discounted present value of reserves used in borrowing base determination   95.00%   85.00%          
Ratio of indebtedness to assets       3.50          
Minimum consolidated interest coverage ratio       2.25          
Ratio of indebtedness to assets       0.38          
Interest coverage ratio       37.89          
Credit Facility [Member] | Revolving Credit Facility | Minimum | Base Rate                  
Debt Instrument [Line Items]                  
Basis spread on variable rate 1.00% 2.00%              
Credit Facility [Member] | Revolving Credit Facility | Minimum | LIBOR                  
Debt Instrument [Line Items]                  
Basis spread on variable rate 2.00% 3.00%              
Credit Facility [Member] | Revolving Credit Facility | Maximum | Base Rate                  
Debt Instrument [Line Items]                  
Basis spread on variable rate 2.00% 3.00%              
Credit Facility [Member] | Revolving Credit Facility | Maximum | LIBOR                  
Debt Instrument [Line Items]                  
Basis spread on variable rate 3.00% 4.00%              
New Building Note [Member] | Secured Notes                  
Debt Instrument [Line Items]                  
Repayments of long-term debt     $ 36,300,000            
Repurchased face amount     35,000,000.0            
Paid-in-kind interest     $ 1,300,000            
Gain on extinguishment of debt         $ 1,200,000