Schedule I - Condensed Parent Company Finanical Statements (Details-Notes 2) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
MGE Energy [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 75,194	$ 65,990	$ 67,112
First Mortgage Bonds [Member] | 7.70%, 2028 Series [Member]
Dividend Restrictions
Debt covenant, allowable amount available for payment of dividends	807,200
MGE [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 51,500	34,500	41,000
Dividend Restrictions
Common equity ratio	0.58
MGE [Member] | Minimum [Member]
Dividend Restrictions
Dividend restrictions, common equity ratio	0.55
MAGAEL [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 0	2,000	0
CWDC [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	0	2,000	0
MGE Power Elm Road [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	15,000	15,000	14,250
MGE Power West Campus [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	1,250	7,000	6,250
MGE Transco [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	7,157	5,230	5,533
MGEE Transco [Member]
Dividends from Affiliates [Line Items]
Cash dividends paid to parent by MGE	$ 287	$ 260	$ 79