Note 18 - Segment of Business - Summary of Reportable Segments Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Revenue	$ 109,672	$ 188,334
Operating Expense	2,733	29,233
Depreciation	15,443	17,976
Assets	585,420	616,627	$ 589,780
Capital Expenditures	14,874	13,482
Electric Operations [Member]
Revenue	58,912	92,494
Operating Expense	15,247	18,705
Depreciation	4,697	4,675
Assets	211,116	218,132
Capital Expenditures	6,242	843
Coal Operations [Member]
Revenue	66,870	95,273
Operating Expense	(11,457)	13,088
Depreciation	10,728	13,275
Assets	370,292	391,248
Capital Expenditures	8,632	12,639
Corporate Segment and Other Operating Segment [Member]
Revenue	(16,110)	567
Operating Expense	(1,057)	(2,560)
Depreciation	18	26
Assets	4,012	7,247
Capital Expenditures	$ 0	$ 0