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Investment in ATC and ATC Holdco (Details-1) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment				$ 7,930	$ 6,626
Dividends from investments				6,305	5,964
Capital contributions to investments				5,986	3,938
MGE Transco [Member] \| ATC [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment		$ 2,662	$ 1,473	7,844	6,543
Dividends from investments		2,057	2,005	6,305	5,964
Capital contributions to investments		$ 1,075	$ 536	$ 3,033	$ 2,319
MGE Transco [Member] \| ATC [Member] \| Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Capital contributions to investments	$ 700