Note 14 - Merom Acquisition - Summary of Acquired Assets and Liabilities (Details) - USD ($) $ in Thousands	Oct. 21, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Plant		$ 476,220	$ 480,462
Coal inventory		49,411	49,796
Amount attributable to assets acquired		616,627	630,554	$ 357,876
Amount attributable to liabilities assumed		$ 379,441	$ 415,530
Merom Acquisition [Member]
Direct transaction costs	$ 2,855
Contract liability - PPA	184,500
Contract liability - Capacity payment reduction	11,000
Contract asset - Coal purchase agreement	(34,300)
Coal inventory purchased	5,400
Deferred coal inventory payment	11,600
Total consideration	181,055
Plant	165,816
Materials and supplies	12,009
Coal inventory	10,460
Amount attributable to assets acquired	188,285
Asset retirement obligations	7,230
Amount attributable to liabilities assumed	$ 7,230