{"cik":61339,"taxonomy":"us-gaap","tag":"EarningsPerShareBasic","label":"Earnings Per Share, Basic","description":"The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.","entityName":"MGE Energy, Inc.","units":{"USD/shares":[{"start":"2023-01-01","end":"2023-12-31","val":3.25,"accn":"0001193125-26-083622","fy":2025,"fp":"FY","form":"10-K","filed":"2026-03-02","frame":"CY2023"},{"start":"2024-01-01","end":"2024-12-31","val":3.33,"accn":"0001193125-26-083622","fy":2025,"fp":"FY","form":"10-K","filed":"2026-03-02","frame":"CY2024"},{"start":"2025-01-01","end":"2025-06-30","val":1.86,"accn":"0001193125-26-333969","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-08-05"},{"start":"2025-04-01","end":"2025-06-30","val":0.73,"accn":"0001193125-26-333969","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-08-05","frame":"CY2025Q2"},{"start":"2025-01-01","end":"2025-12-31","val":3.72,"accn":"0001193125-26-083622","fy":2025,"fp":"FY","form":"10-K","filed":"2026-03-02","frame":"CY2025"},{"start":"2026-01-01","end":"2026-06-30","val":2.21,"accn":"0001193125-26-333969","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-08-05"},{"start":"2026-04-01","end":"2026-06-30","val":0.89,"accn":"0001193125-26-333969","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-08-05","frame":"CY2026Q2"}]}}