Note 2 - Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Restricted Cash
Restricted Cash	$ 800	$ 900
Restricted Cash, Asset, Statement of Financial Position [Extensible List]	Other assets	Other assets
Inventories
Raw Coal	$ 20,122	$ 22,414
Saleable Coal	12,013	18,223
Coal Supplies	5,028	4,336
Supply inventory	$ 37,163	$ 44,973