Note 5 - Derivative Financial Instruments - Net Derivative Liabilities By Counterparty (Details) - Commodity Contract [Member] $ in Thousands	Jun. 30, 2022 USD ($)
Net derivative liabilities	$ (31,909)
Fifth Third Bank, National Association [Member]
Net derivative liabilities	(22,656)
Bank of America, National Association [Member]
Net derivative liabilities	(9,643)
Bank of Oklahoma, National Association [Member]
Net derivative liabilities	(3,668)
Citizens Bank, National Association [Member]
Commodity price derivatives	$ 4,058