Note 5 - Derivative Financial Instruments - Net Derivative Liabilities By Counterparty (Details) - Commodity Contract [Member] $ in Thousands	Sep. 30, 2023 USD ($)
Macquarie Bank Limited	$ 27,242
Deriviative liabilities	27,242
Fifth Third Bank, National Association	(27,242)
Macquarie Bank Limited [Member]
Macquarie Bank Limited	(16,697)
Deriviative liabilities	(16,697)
Fifth Third Bank, National Association	16,697
Wells Fargo Bank, National Association [Member]
Macquarie Bank Limited	(10,034)
Deriviative liabilities	(10,034)
Fifth Third Bank, National Association	10,034
Mercuria Energy Trading SA [Member]
Macquarie Bank Limited	(888)
Deriviative liabilities	(888)
Fifth Third Bank, National Association	888
Fifth Third Bank, National Association [Member]
Macquarie Bank Limited	(377)
Deriviative liabilities	(377)
Fifth Third Bank, National Association	$ 377