Quarterly report pursuant to Section 13 or 15(d)

Long-term Debt (Details Textual)

v3.21.2
Long-term Debt (Details Textual)
$ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Nov. 02, 2021
agreement
Sep. 30, 2021
USD ($)
Sep. 30, 2020
USD ($)
Sep. 30, 2021
USD ($)
item
Sep. 30, 2020
USD ($)
Dec. 31, 2020
USD ($)
May 19, 2021
USD ($)
Oct. 18, 2018
USD ($)
Current portion of long-term debt   $ 46,201   $ 46,201        
Repayments of outstanding balance       80,000 $ 50,000      
Gain (Loss) on Extinguishment of Debt, Total   0 $ 0 0 $ 47,469      
Subsequent Event                
Number of amendments in credit agreement | agreement 2              
Term Loan [Member]                
Current portion of long-term debt   46,200   46,200        
Debt Instrument, Face Amount             $ 215,000  
Debt Instrument, Interest Rate, Stated Percentage             7.00%  
Credit Agreement [Member]                
Repayments of outstanding balance       48,000        
Borrowings outstanding   0   0   $ 80,000    
Line of Credit Facility, Maximum Borrowing Capacity   190,000   $ 190,000        
Credit Agreement, Maximum Leverage Ratio       3.00        
Credit Agreement, Leverage Ratio       2.00        
Number of trailing quarters | item       4        
Credit Agreement, Minimum Current Ratio       1.00        
Credit Agreement, Minimum Percentage of Total Proved Reserves       90.00%        
Letters of Credit Outstanding, Amount   4,400   $ 4,400   4,400    
Line of Credit Facility, Interest Rate During Period       3.20%        
Credit Agreement [Member] | Letter of Credit [Member]                
Line of Credit Facility, Maximum Borrowing Capacity   30,000   $ 30,000        
Senior Second Lien Notes Due November 2023 [Member]                
Debt Instrument, Face Amount   $ 552,500   $ 552,500   552,500   $ 625,000
Debt Instrument, Interest Rate, Stated Percentage               9.75%
Debt Instrument, Interest Rate, Effective Percentage               10.30%
Extinguishment of Debt, Amount           72,500    
Repayments of Long-term Debt, Total           23,900    
Gain (Loss) on Extinguishment of Debt, Total           47,500    
Write off of Deferred Debt Issuance Cost           $ 1,100