Note 7 - Long-term Debt (Details Textual) - USD ($)		1 Months Ended		3 Months Ended		12 Months Ended
		Feb. 28, 2022	Dec. 31, 2020	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Oct. 01, 2021	Jun. 30, 2021
Debt Instrument, Unamortized Discount, Total	[1]			$ 13,927,000			$ (0)
Payments of Debt Issuance Costs				6,449,000	$ 2,000
Senior Unsecured Notes Due 2024 [Member]
Debt Instrument, Unamortized Discount, Total		$ 14,800,000
Debt Instrument, Face Amount		$ 225,000,000.0
Long-Term Debt, Gross				225,000,000			0
Debt Instrument, Interest Rate, Stated Percentage		10.00%
Payments of Debt Issuance Costs		$ 21,200,000
Proceeds from Issuance of Debt		203,800,000
Revolving Credit Facility [Member]
Long-Term Debt, Gross				0			100,000,000
Revolving Credit Facility [Member] | Fifth Third Bank, National Association [Member]
Line of Credit Facility, Maximum Borrowing Capacity			$ 40,000,000.0			$ 40,000,000.0		$ 195,000,000.0	$ 125,000,000.0
Line of Credit Facility, Commitment Fee Amount			20,000,000.0
Line of Credit Facility, Current Borrowing Capacity		$ 138,800,000	$ 20,000,000.0			$ 20,000,000.0		$ 195,000,000.0	$ 125,000,000.0
Debt Instrument, Face Amount							500,000,000.0
Long-Term Debt, Gross				$ 0			100,000,000.0
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.50%
Debt Instrument, Covenant, Minimum Cash Threshold for Prepayment to be Due				$ 20,000,000.0
Revolving Credit Facility [Member] | Fifth Third Bank, National Association [Member] | Maximum [Member]
Debt Instrument, Covenant, Maximum Total Debt to EBITDAX Ratio				3.00
Revolving Credit Facility [Member] | Fifth Third Bank, National Association [Member] | Minimum [Member]
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%
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 Issuance Costs, Gross				$ 9,000,000.0			2,600,000
Accumulated Amortization, Debt Issuance Costs				1,100,000			502,000
Debt Instrument, Unamortized Discount, Total				14,800,000			0
Accumulated Amortization, Debt Discount				$ 893,000			$ 0

[1] Discounts as of March 31, 2022 and December 31, 2021 consisted of $14.8 million and zero, respectively, in discounts less accumulated amortization of $893,000 and zero, respectively.