Schedule I - Condensed Parent Company Finanical Statements (Details-Comprehensive Income Statement) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Utilities Operating Expense [Abstract]
Other operations and maintenance	$ 228,576	$ 215,891	$ 209,875
Total Operating Expenses	530,682	544,046	576,776
Operating Income	146,262	146,385	137,743
Equity earnings of investments	12,275	10,631	9,136
Income before income taxes	131,165	145,502	137,176
Income tax provision	(10,596)	(27,803)	(26,224)
Net Income	120,569	117,699	110,952
MGE Energy [Member]
Utilities Operating Expense [Abstract]
Other operations and maintenance	818	868	746
Total Operating Expenses	818	868	746
Operating Income	(818)	(868)	(746)
Equity earnings of investments	121,310	120,394	112,180
Other income/(loss), net	(395)	(2,862)	(855)
Interest income, net	296	105	2
Income before income taxes	120,393	116,769	110,581
Income tax provision	175	930	371
Net Income	$ 120,568	$ 117,699	$ 110,952