Schedule I - Condensed Parent Company Finanical Statements (Details-Comprehensive Income Statement) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Utilities Operating Expense [Abstract]
Other operations and maintenance	$ 215,891	$ 209,875	$ 199,316
Total Operating Expenses	544,046	576,776	489,290
Operating Income	146,385	137,743	117,294
Equity earnings of investments	10,631	9,136	9,270
Income before income taxes	145,502	137,176	109,876
Income tax provision	(27,803)	(26,224)	(4,115)
Net Income	117,699	110,952	105,761
MGE Energy [Member]
Utilities Operating Expense [Abstract]
Other operations and maintenance	868	746	711
Total Operating Expenses	868	746	711
Operating Income	(868)	(746)	(711)
Equity earnings of investments	120,394	112,180	107,883
Other income/(loss), net	(2,862)	(855)	(2,163)
Interest income, net	105	2	5
Income before income taxes	116,769	110,581	105,014
Income tax provision	930	371	747
Net Income	$ 117,699	$ 110,952	$ 105,761