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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, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment				$ 6,626	$ 7,440
Dividends from investment				5,964	5,842
Capital contributions to investments				3,938	4,227
MGE Transco [Member] \| ATC [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment		$ 1,473	$ 2,500	6,543	7,333
Dividends from investment		2,005	1,942	5,964	5,842
Capital contributions to investments		$ 536	$ 0	$ 2,319	$ 0
MGE Transco [Member] \| ATC [Member] \| Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Capital contributions to investments	$ 400