Schedule I - Condensed Parent Company Finanical Statements (Details-Cash Flow Statement) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by operating activities	$ 277,784	$ 237,561	$ 153,735
Investing Activities:
Other	230	(954)	70
Cash used for investing activities	(241,487)	(230,020)	(180,145)
Financing Activities:
Proceeds from Issuance of Common Stock	31,605	0	0
Cash dividends paid on common stock	(63,596)	(60,393)	(57,500)
Other	(1,690)	(2,576)	(2,068)
Cash (Used for) Provided by Financing Activities	(26,827)	(10,483)	25,543
Change in cash, cash equivalents, and restricted cash:	9,470	(2,942)	(867)
Cash, cash equivalents, and restricted cash at beginning of period	15,026	17,968	18,835
Cash, cash equivalents, and restricted cash at end of period	24,496	15,026	17,968
MGE Energy [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Cash provided by operating activities	65,883	67,253	58,253
Investing Activities:
Contributions to affiliates	(33,429)	(3,750)	(2,693)
Contributions to other Investments	(1,964)	(3,080)	(2,357)
Other	329	987	861
Cash used for investing activities	(35,064)	(5,843)	(4,189)
Financing Activities:
Proceeds from Issuance of Common Stock	31,712	0	0
Cash dividends paid on common stock	(63,595)	(60,393)	(57,500)
Other	(94)	0	(187)
Cash (Used for) Provided by Financing Activities	(31,977)	(60,393)	(57,687)
Change in cash, cash equivalents, and restricted cash:	(1,158)	1,017	(3,623)
Cash, cash equivalents, and restricted cash at beginning of period	4,353	3,336	6,959
Cash, cash equivalents, and restricted cash at end of period	$ 3,195	$ 4,353	$ 3,336