SEGMENTS OF BUSINESS - Assets And Capital Expenditure (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025	Dec. 31, 2024
SEGMENTS OF BUSINESS
Assets	$ 448,632	$ 366,097	$ 408,053	$ 369,120
Capital Expenditures	7,681	11,693
Cash and cash equivalents	36,778	6,891	10,070
Operating Segment | Electric Operations
SEGMENTS OF BUSINESS
Assets	254,332	222,865	256,529	220,477
Capital Expenditures	3,889	5,449
Operating Segment | Coal Operations
SEGMENTS OF BUSINESS
Assets	184,915	141,023	148,957	144,519
Capital Expenditures	3,792	6,244
Cash and cash equivalents	36,300	5,600	9,400	6,900
Corporate and Other and Eliminations
SEGMENTS OF BUSINESS
Assets	$ 9,385	$ 2,209	$ 2,567	$ 4,124