Consolidated Statements of Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating Revenues:
Electric revenues	$ 102,076,000	$ 93,961,000	$ 202,721,000	$ 186,989,000
Gas revenue	28,654,000	23,079,000	95,924,000	79,924,000
Total Operating Revenues	130,730,000	117,040,000	298,645,000	266,913,000
Operating Expenses:
Fuel for electric generation	10,913,000	8,692,000	24,084,000	18,398,000
Purchased power	10,913,000	10,856,000	20,268,000	21,342,000
Cost of gas sold	11,504,000	6,339,000	48,948,000	37,137,000
Other operations and maintenance	50,387,000	46,224,000	96,069,000	90,593,000
Depreciation and amortization	18,595,000	18,434,000	36,977,000	36,601,000
Other general taxes	5,025,000	4,975,000	9,852,000	9,882,000
Total Operating Expenses	107,337,000	95,520,000	236,198,000	213,953,000
Operating Income	23,393,000	21,520,000	62,447,000	52,960,000
Other (expense) income, net	6,110,000	6,925,000	8,188,000	12,596,000
Interest expense, net	(5,771,000)	(5,914,000)	(11,511,000)	(11,975,000)
Income before income taxes	23,732,000	22,531,000	59,124,000	53,581,000
Income tax benefit (provision)	(881,000)	(3,740,000)	(1,340,000)	(8,753,000)
Net Income Including Noncontrolling Interest	22,851,000	18,791,000	57,784,000	44,828,000
Net Income	$ 22,851,000	$ 18,791,000	$ 57,784,000	$ 44,828,000
Earnings per share of Common Stock - Basic	$ 0.63	$ 0.53	$ 1.60	$ 1.28
Earnings per share of Common Stock - Diluted	0.63	0.53	1.60	1.28
Dividends per share of common stock	$ 0.37	$ 0.353	$ 0.740	$ 0.705
Weighted Average Number Of Shares Outstanding Basic	36,163,000	35,441,000	36,163,000	35,054,000
Weighted Average Shares Outstanding - Diluted	36,168,000	35,441,000	36,170,000	35,054,000
MGE [Member]
Operating Revenues:
Electric revenues	$ 102,076,000	$ 93,961,000	$ 202,721,000	$ 186,989,000
Gas revenue	28,654,000	23,079,000	95,924,000	79,924,000
Total Operating Revenues	130,730,000	117,040,000	298,645,000	266,913,000
Operating Expenses:
Fuel for electric generation	10,913,000	8,692,000	24,084,000	18,398,000
Purchased power	10,913,000	10,856,000	20,268,000	21,342,000
Cost of gas sold	11,504,000	6,339,000	48,948,000	37,137,000
Other operations and maintenance	50,125,000	45,893,000	95,663,000	90,043,000
Depreciation and amortization	18,595,000	18,434,000	36,977,000	36,601,000
Other general taxes	5,025,000	4,975,000	9,852,000	9,882,000
Total Operating Expenses	107,075,000	95,189,000	235,792,000	213,403,000
Operating Income	23,655,000	21,851,000	62,853,000	53,510,000
Other (expense) income, net	3,173,000	3,531,000	3,069,000	6,911,000
Interest expense, net	(5,781,000)	(5,935,000)	(11,534,000)	(12,046,000)
Income before income taxes	21,047,000	19,447,000	54,388,000	48,375,000
Income tax benefit (provision)	(293,000)	(3,046,000)	140,000	(7,417,000)
Net Income Including Noncontrolling Interest	20,754,000	16,401,000	54,528,000	40,958,000
Less Net Income Attributable to Noncontrolling Interest, net of tax	(5,627,000)	(5,768,000)	(11,128,000)	(11,261,000)
Net Income	$ 15,127,000	$ 10,633,000	$ 43,400,000	$ 29,697,000