Note 18 - Segment of Business - Summary of Reportable Segments Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Revenue	$ 634,480	$ 361,991
Operating Expense	65,012	30,430
Depreciation	67,211	46,875
Amount attributable to assets acquired	589,780	630,554
Capital Expenditures	75,352	54,020
Coal Operations [Member]
Revenue	435,425	293,344
Operating Expense	63,600	3,736
Depreciation	48,365	43,612
Amount attributable to assets acquired	376,387	376,228
Capital Expenditures	56,521	50,367
Electric Operations [Member]
Revenue	268,341	66,316
Operating Expense	12,552	31,505
Depreciation	18,739	3,117
Amount attributable to assets acquired	208,331	266,730
Capital Expenditures	18,831	3,653
Corporate and Other [Member]
Revenue	(69,286)	2,331
Operating Expense	(11,140)	(4,811)
Depreciation	107	146
Amount attributable to assets acquired	5,062	(12,404)
Capital Expenditures	$ 0	$ 0