Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating Activities:
Net Income	$ 97,616	$ 89,901
Items not affecting cash:
Depreciation and amortization	74,971	63,780
Deferred income taxes	16,326	18,021
Provision for doubtful receivables	1,323	1,323
Employee benefit plan cost (credit)	(2,976)	(6,087)
Equity earnings in investments	(7,930)	(6,626)
Other items	(2,502)	(2,821)
Changes in working capital items:
Decrease (increase) in current assets	33,976	(5,992)
(Decrease) increase in accounts payable	(16,586)	66
Decrease in other current liabilities	(3,714)	(5,897)
Dividends from investments	6,305	5,964
Cash contributions to pension and other postretirement plans	(5,290)	(5,095)
Other noncurrent items, net	2,519	(2,255)
Cash Provided by Operating Activities	194,038	144,282
Investing Activities:
Capital expenditures	(150,298)	(133,409)
Capital contributions to investments	(5,986)	(3,938)
Other	(206)	128
Cash Used for Investing Activities	(156,490)	(137,219)
Financing Activities:
Cash dividends paid on common stock	(44,933)	(42,763)
Repayments of long-term debt	(53,048)	(3,655)
Issuance of long-term debt	109,300	0
(Repayments of) proceeds from short-term debt	(48,500)	34,500
Other	(2,128)	(745)
Cash Used for Financing Activities	(39,309)	(12,663)
Change in cash, cash equivalents, and restricted cash	(1,761)	(5,600)
Cash, cash equivalents, and restricted cash at beginning of period	17,968	18,835
Cash, cash equivalents, and restricted cash at end of period	16,207	13,235
Significant noncash investing activities:
Accrued capital expenditures	17,716	11,218
MGE [Member]
Operating Activities:
Net Income	93,202	84,481
Items not affecting cash:
Depreciation and amortization	74,971	63,780
Deferred income taxes	15,218	17,706
Provision for doubtful receivables	1,323	1,323
Employee benefit plan cost (credit)	(2,976)	(6,087)
Other items	(2,604)	(636)
Changes in working capital items:
Decrease (increase) in current assets	33,076	(7,238)
(Decrease) increase in accounts payable	(16,583)	64
Decrease in other current liabilities	(1,809)	(3,706)
Cash contributions to pension and other postretirement plans	(5,290)	(5,095)
Other noncurrent items, net	1,840	(2,806)
Cash Provided by Operating Activities	190,368	141,786
Investing Activities:
Capital expenditures	(150,298)	(133,409)
Other	(1,338)	(680)
Cash Used for Investing Activities	(151,636)	(134,089)
Financing Activities:
Cash dividends paid to parent by MGE	(30,000)	(21,000)
Distributions to parent from noncontrolling interest	(17,250)	(17,500)
Repayments of long-term debt	(53,048)	(3,655)
Issuance of long-term debt	109,300	0
(Repayments of) proceeds from short-term debt	(48,500)	34,500
Other	(2,128)	(745)
Cash Used for Financing Activities	(41,626)	(8,400)
Change in cash, cash equivalents, and restricted cash	(2,894)	(703)
Cash, cash equivalents, and restricted cash at beginning of period	10,500	7,798
Cash, cash equivalents, and restricted cash at end of period	7,606	7,095
Significant noncash investing activities:
Accrued capital expenditures	$ 17,716	$ 11,218