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Investment in ATC and ATC Holdco (Details-1) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jul. 31, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment				$ 5,240	$ 5,127
Dividends from investments				4,248	3,959
Capital contributions to investments				3,376	3,330
MGE Transco [Member] \| ATC [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment		$ 2,599	$ 2,592	5,182	5,070
Dividends from investments		2,042	1,958	4,248	3,959
Capital contributions to investments		$ 1,601	$ 540	$ 1,958	$ 1,783
MGE Transco [Member] \| ATC [Member] \| Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Capital contributions to investments	$ 1,100