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Derivatives - Narrative (Details)
bbl in Thousands
12 Months Ended
Dec. 31, 2020
$ / bbl
bbl
Dec. 31, 2018
USD ($)
Feb. 28, 2018
USD ($)
Jun. 30, 2016
USD ($)
Credit Derivatives [Line Items]        
Derivative contracts, barrels | bbl 550      
Derivative, average fixed interest rate 3.91%      
5.00% Convertible Senior Notes due 2021        
Credit Derivatives [Line Items]        
Debt instrument, interest rate 5.00%     5.00%
5.00% Convertible Senior Notes due 2021 | Convertible Debt        
Credit Derivatives [Line Items]        
Aggregate principal amount       $ 115,000,000.0
Debt instrument, interest rate 5.00%     5.00%
Option Collars        
Credit Derivatives [Line Items]        
Derivative contracts, barrels | bbl 25      
Option Collars | Minimum        
Credit Derivatives [Line Items]        
Derivative, average price risk option strike price | $ / bbl 36.50      
Option Collars | Maximum        
Credit Derivatives [Line Items]        
Derivative, average price risk option strike price | $ / bbl 60.00      
Interest Rate Swap        
Credit Derivatives [Line Items]        
Notional amount     $ 100,000,000  
Termination of derivative gain (loss)   $ 3,700,000