Quarterly report pursuant to Section 13 or 15(d)

Note 2 - Long-term Debt (Details Textual)

v3.19.3
Note 2 - Long-term Debt (Details Textual)
$ in Thousands
3 Months Ended 6 Months Ended 9 Months Ended
Dec. 31, 2019
Sep. 30, 2019
USD ($)
Sep. 30, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2026
Dec. 31, 2018
USD ($)
Oct. 18, 2018
USD ($)
Credit Agreement, Maximum Leverage Ratio Following Material Acquisition         3.5    
Credit Agreement [Member]              
Line of Credit Facility, Maximum Borrowing Capacity             $ 250,000
Letters of Credit Outstanding, Amount   $ 7,200 $ 7,200 $ 7,200   $ 9,600  
Credit Agreement, Maximum Leverage Ratio   3 3.25        
Credit Agreement, Minimum Current Ratio     1        
Credit Agreement, Minimum Percentage of Total Proved Reserves     85.00%        
Debt Instrument, Interest Rate During Period       5.10%      
Credit Agreement [Member] | Forecast [Member]              
Credit Agreement, Maximum Leverage Ratio 3            
Credit Agreement [Member] | Letter of Credit [Member]              
Line of Credit Facility, Maximum Borrowing Capacity             30,000
Senior Second Lien Notes Due November 2023 [Member]              
Debt Instrument, Face Amount   $ 625,000 $ 625,000 $ 625,000   $ 625,000 $ 625,000
Debt Instrument, Interest Rate, Stated Percentage             9.75%
Debt Instrument, Interest Rate, Effective Percentage             10.30%