Schedule I - Condensed Parent Company Finanical Statements (Details-Comprehensive Income Statement) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Utilities Operating Expense [Abstract]
Other operations and maintenance	$ 209,875	$ 199,316	$ 186,430
Total Operating Expenses	576,776	489,290	428,636
Operating Income	137,743	117,294	109,997
Equity earnings of investments	9,136	9,270	10,221
Income before income taxes	137,176	109,876	111,841
Income tax provision	(26,224)	(4,115)	(19,423)
Net Income	110,952	105,761	92,418
MGE Energy [Member]
Utilities Operating Expense [Abstract]
Other operations and maintenance	746	711	882
Total Operating Expenses	746	711	882
Operating Income	(746)	(711)	(882)
Equity earnings of investments	112,180	107,883	92,922
Other income/(loss), net	(855)	(2,163)	94
Interest income, net	2	5	78
Income before income taxes	110,581	105,014	92,212
Income tax provision	371	747	206
Net Income	$ 110,952	$ 105,761	$ 92,418