Annual report pursuant to Section 13 and 15(d)

Note 2 - Long-term Debt (Details Textual)

v3.20.4
Note 2 - Long-term Debt (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Oct. 18, 2018
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Jan. 06, 2021
Long-Term Debt, Maturity, Year One   $ 0      
Long-Term Debt, Maturity, Year Two   80,000      
Long-Term Debt, Maturity, Year Three   552,500      
Gain (Loss) on Extinguishment of Debt, Total   47,469 $ (0) $ 47,109  
Refinancing Transaction [Member]          
Gain (Loss) on Extinguishment of Debt, Total $ 47,100     $ 47,100  
Basic Earnings Per Share Adjustment, Pro Forma (in dollars per share) $ 0.33        
Senior Second Lien Notes Due November 2023 [Member]          
Debt Instrument, Face Amount $ 625,000 552,460 625,000    
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      
Senior Second Lien Notes Due November 2023 [Member] | Debt Instrument, Redemption, Period One [Member]          
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed   104.875%      
Senior Second Lien Notes Due November 2023 [Member] | Debt Instrument, Redemption, Period Two [Member]          
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed   102.438%      
Senior Second Lien Notes Due November 2023 [Member] | Debt Instrument, Redemption, Period Three [Member]          
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed   100.00%      
Senior Second Lien Notes Due November 2023 [Member] | Debt Instrument, Redemption, Period Four [Member]          
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed   101.00%      
Credit Agreement [Member]          
Line of Credit Facility, Maximum Borrowing Capacity   $ 215,000      
Credit Agreement, Maximum Leverage Ratio   3.00      
Credit Agreement, Leverage Ratio   2.00      
Credit Agreement, Minimum Current Ratio   1.00      
Credit Agreement, Minimum Percentage of Total Proved Reserves   90.00%      
Commitment Fee if Borrowing Base Utilization Percentage is Below 50%   0.50%      
Debt Instrument, Covenant, Minimum Percentage of Derivative Contracts   50.00%      
Letters of Credit Outstanding, Amount   $ 4,400 $ 5,800    
Line of Credit Facility, Interest Rate During Period   3.80%      
Credit Agreement [Member] | Subsequent Event [Member]          
Line of Credit Facility, Maximum Borrowing Capacity         $ 190,000
Debt Instrument, Anti-cash Hoarding Prepayment, Maximum Cash Balance Threshold         $ 25,000
Credit Agreement [Member] | Minimum [Member] | Eurodollar [Member]          
Debt Instrument, Basis Spread on Variable Rate   2.75%      
Credit Agreement [Member] | Minimum [Member] | Base Rate [Member]          
Debt Instrument, Basis Spread on Variable Rate   1.75%      
Credit Agreement [Member] | Maximum [Member] | Eurodollar [Member]          
Debt Instrument, Basis Spread on Variable Rate   3.75%      
Credit Agreement [Member] | Maximum [Member] | Base Rate [Member]          
Debt Instrument, Basis Spread on Variable Rate   2.75%      
Credit Agreement [Member] | Line of Credit [Member]          
Line of Credit Facility, Maximum Borrowing Capacity   $ 30,000      
11.00% 1.5 Lien Term Loan Due November 2019 [Member] | Refinancing Transaction [Member]          
Debt Instrument, Interest Rate, Stated Percentage 11.00%        
Extinguishment of Debt, Amount $ 75,000        
The Nine Percent Term Loan, due May 15, 2020 [Member] | Refinancing Transaction [Member]          
Debt Instrument, Interest Rate, Stated Percentage 9.00%        
Extinguishment of Debt, Amount $ 300,000        
Second Lien PIK Toggle Notes [Member] | Refinancing Transaction [Member]          
Extinguishment of Debt, Amount $ 177,500        
Second Lien PIK Toggle Notes [Member] | Minimum [Member] | Refinancing Transaction [Member]          
Debt Instrument, Interest Rate, Stated Percentage 9.00%        
Second Lien PIK Toggle Notes [Member] | Maximum [Member] | Refinancing Transaction [Member]          
Debt Instrument, Interest Rate, Stated Percentage 10.75%        
Third Lien PIK Toggle Notes [Member] | Refinancing Transaction [Member]          
Extinguishment of Debt, Amount $ 160,900        
Third Lien PIK Toggle Notes [Member] | Minimum [Member] | Refinancing Transaction [Member]          
Debt Instrument, Interest Rate, Stated Percentage 8.50%        
Third Lien PIK Toggle Notes [Member] | Maximum [Member] | Refinancing Transaction [Member]          
Debt Instrument, Interest Rate, Stated Percentage 10.00%        
Unsecured Senior Notes [Member] | Refinancing Transaction [Member]          
Debt Instrument, Interest Rate, Stated Percentage 8.50%        
Extinguishment of Debt, Amount $ 189,800