Note 7 - Long-term Debt (Details Textual) $ in Thousands			1 Months Ended				3 Months Ended		12 Months Ended
		Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Nov. 30, 2022 USD ($)	Feb. 28, 2022 USD ($)	Dec. 31, 2020 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 14, 2022 USD ($)	Nov. 14, 2022 USD ($)	Oct. 31, 2022 USD ($)	Oct. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)
Debt Instrument, Unamortized Discount, Total	[1]		$ 27,086				$ 22,796		$ 27,086
Payments of Debt Issuance Costs							544	$ 6,449
Senior Unsecured Notes Due 2024 [Member]
Debt Instrument, Unamortized Discount, Total							34,800
Debt Instrument, Face Amount			250,000	$ 225,000	$ 225,000				250,000
Long-Term Debt, Gross			225,000				$ 225,000		225,000
Debt Instrument, Interest Rate, Stated Percentage					10.00%		10.00%
Payments of Debt Issuance Costs					$ 22,100
Proceeds from Issuance of Debt					202,900
The 10.625% Senior Notes [Member]
Debt Instrument, Face Amount										$ 25,000	$ 225,000
Debt Instrument, Interest Rate, Stated Percentage							10.625%				10.625%
Payments of Debt Issuance Costs				26,300
Proceeds from Issuance of Debt				$ 223,700
Revolving Credit Facility [Member]
Long-Term Debt, Gross			270,000				$ 420,000		$ 270,000
Revolving Credit Facility [Member] | Fifth Third Bank, National Association [Member]
Line of Credit Facility, Maximum Borrowing Capacity		$ 400,000			138,800	$ 40,000	700,000					$ 550,000	$ 195,000	$ 125,000
Line of Credit Facility, Commitment Fee Amount			575,000			20,000	575,000
Line of Credit Facility, Current Borrowing Capacity		400,000			138,800	$ 20,000	125,000					525,000	$ 195,000
Debt Instrument, Covenant, Minimum Cash Threshold for Prepayment to be Due		75,000					75,000					$ 250,000
Debt Instrument, Covenant, Maximum Total Debt to EBITDAX Ratio									3.00
Debt Instrument, Covenant, Dividends and Distributions Limit							4,000
Long-Term Debt, Gross			270,000		$ 0		420,000		$ 270,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage					0.50%
Debt Instrument, Covenant, Minimum Current Ratio									1.00
Revolving Credit Facility [Member] | Fifth Third Bank, National Association [Member] | Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate						0.50%
Revolving Credit Facility [Member] | Fifth Third Bank, National Association [Member] | Maximum [Member]
Debt Instrument, Face Amount		$ 1,500					1,500,000
Debt Instrument, Covenant, Maximum Total Debt to EBITDAX Ratio		1.75
Revolving Credit Facility [Member] | Fifth Third Bank, National Association [Member] | Minimum [Member]
Debt Instrument, Covenant, Maximum Total Debt to EBITDAX Ratio		1.25
Letter of Credit [Member] | Fifth Third Bank, National Association [Member] | London Interbank Offered Rate (LIBOR), Applicable Margin [Member]
Debt Instrument, Basis Spread on Variable Rate					0.125%
Other Noncurrent Assets [Member]
Debt Instrument, Unamortized Discount, Total			34,800				34,800		$ 34,800
Accumulated Amortization, Debt Discount			7,700				12,000		7,700
Debt Issuance Costs, Gross			19,700				20,200		19,700
Accumulated Amortization, Debt Issuance Costs			$ 6,100				$ 8,800		$ 6,100

[1] Discounts as of March 31, 2023 and December 31, 2022 consisted of $34.8 million and $34.8 million, respectively, in discounts less accumulated amortization of $12.0 million and $7.7 million, respectively.