Note 5 - Asset Retirement Obligations - Schedule of Retirement Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation Disclosure [Abstract]
Balance at beginning of year	$ 28,960	$ 28,885
Additional asset retirement obligations acquired/incurred	470	542
Expenditures made	(237)
Accretion expense	1,465	1,403	$ 1,115
Revisions to estimates	429	(1,870)
Balance at end of year	$ 31,087	$ 28,960	$ 28,885