Quarterly report pursuant to Section 13 or 15(d)

Note 2 - Long-term Debt (Details Textual)

v3.20.2
Note 2 - Long-term Debt (Details Textual) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 17, 2020
Oct. 18, 2018
Jun. 30, 2020
Jun. 30, 2019
Jun. 30, 2020
Jun. 30, 2019
Dec. 31, 2019
Gain (Loss) on Extinguishment of Debt, Total     $ 28,968 $ (0) $ 47,469 $ (0)  
Credit Agreement [Member]              
Line of Credit Facility, Maximum Borrowing Capacity $ 215,000 $ 250,000          
Debt Instrument, Interest Rate, Increase (Decrease) 25.00%            
Credit Agreement, Leverage Ratio 2.00            
Credit Agreement, Minimum Percentage of Total Proved Reserves 90.00% 85.00%          
Debt Instrument, Interest Rate During Period         3.90%    
Letters of Credit Outstanding, Amount     6,100   $ 6,100   $ 5,800
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   $ 625,000 $ 552,460   552,460   $ 625,000
Debt Instrument, Interest Rate, Stated Percentage   9.75%          
Debt Instrument, Interest Rate, Effective Percentage   10.40%          
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