Note 4 - Derivative Instruments - Gain or Losses of Derivative Instruments (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023
Fair value of natural gas derivatives, beginning of period		$ 0
Purchases of natural gas derivatives		359	$ 0
Realized gains (losses), net		(462)	(1,113)
Change in unrealized gain (loss) on natural gas derivatives (1)	[1]	310	541
Fair value of natural gas derivatives, end of year		207	0
Total realized gain (loss) from natural gas derivatives, net (2)		(359)	0
Call Option [Member]
Fair value of natural gas derivatives, beginning of period		0	572
Realized gains (losses), net		(462)	(1,113)
Fair value of natural gas derivatives, end of year		207	0
Derivative settlement payments receivable(ed)		22	0
Total realized gain (loss) from natural gas derivatives, net (2)		$ (440)	$ (1,113)

[1] Amounts are presented on a gross basis.