Investment in ATC and ATC Holdco (Details-1) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
Apr. 30, 2023	Mar. 31, 2023	Mar. 31, 2022
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment		$ 2,611	$ 2,504
Dividends from investments		2,206	2,001
Capital contributions to investments		1,527	1,546
MGE Transco [Member] \| ATC [Member]
Schedule of Equity Method Investments [Line Items]
Equity earnings from investment		2,583	2,478
Dividends from investments		2,206	2,001
Capital contributions to investments		$ 357	$ 1,243
MGE Transco [Member] \| ATC [Member] \| Subsequent Event [Member]
Schedule of Equity Method Investments [Line Items]
Capital contributions to investments	$ 1,600

Amount of distribution received from equity method investee for return on investment, classified as operating activities. Excludes distribution for return of investment, classified as investing activities.

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