Note 11 - Revenue - Domestic Revenues an Export Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
REVENUES
Revenue from Contract with Customer, Including Assessed Tax	$ 666,295	$ 693,524	$ 565,688
Domestic Coal Revenues
REVENUES
Revenue from Contract with Customer, Including Assessed Tax	221,664	227,484	328,322
Export Revenues
REVENUES
Revenue from Contract with Customer, Including Assessed Tax	$ 444,631	$ 466,040	$ 237,366