Note 5 - Derivative Financial Instruments - Net Derivative Liabilities By Counterparty (Details) - Commodity Contract [Member] $ in Thousands	Dec. 31, 2023 USD ($)
Derivative Liabilities	$ 34,420
Mercuria Energy Trading SA [Member]
Derivative Liabilities	19,520
Wells Fargo Bank, National Association [Member]
Derivative Liabilities	7,570
Fifth Third Bank, National Association [Member]
Derivative Liabilities	5,004
Macquarie Bank Limited [Member]
Derivative Liabilities	$ 2,326