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Supplemental Information on Oil and Natural Gas Producing Activities (Unaudited) - Narrative (Details)
 3 Months Ended 12 Months Ended
Dec. 31, 2020
MBoe
Dec. 31, 2020
MBoe
Dec. 31, 2019
MBoe
Dec. 31, 2018
MBoe
Extractive Industries [Abstract]        
Percentage of proved reserves estimates prepared by external engineers 0.90 0.90 0.90  
Proved developed and undeveloped reserves (MBoe) 36,879 36,879 89,885 160,176
Decrease due to change in accounting (MBoe)   50,900 45,000.0  
Decrease due to change in accounting, PUD   27,800 39,800  
Decrease due to change in accounting, Remaining Proved Reserves   17,300 11,100  
Revision of previous estimates due to changes in commodity pricing (MBoe)   10,900    
Revision of previous estimates due to changes in well performance (MBoe)   3,200    
Production (MBoe)   8,703 11,956  
Improved recovery (MBoe)   12,600 8,600  
Revision of previous estimates (MBoe) (9,000.0) (44,800) (58,514)  
Acquisitions of new reserves (MBoe)   1,076