Schedule I - Condensed Parent Company Finanical Statements (Details-Notes 2) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
MGE Energy [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 60,121	$ 25,464	$ 27,714
First Mortgage Bonds [Member] | 7.70%, 2028 Series [Member]
Dividend Restrictions
Debt covenant, allowable amount available for payment of dividends	650,100
MGE [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 33,500	5,000	0
Dividend Restrictions
Common equity ratio	0.605
MGE [Member] | Minimum [Member]
Dividend Restrictions
Dividend restrictions, common equity ratio	0.55
MGE Power Elm Road [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 12,500	10,500	15,500
MGE Power West Campus [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	9,500	4,500	6,000
MGE Transco [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	4,621	5,464	5,864
MGEE Transco [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 0	$ 0	$ 350