Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Activities:
Net Income	$ 34,933,000	$ 26,037,000
Items not affecting cash:
Depreciation and amortization	18,382,000	18,167,000
Deferred income taxes	(796,000)	1,433,000
Provision for doubtful receivables	388,000	734,000
Employee benefit plan cost (credit)	1,461,000	(940,000)
Equity earnings in investments	(2,444,000)	(2,266,000)
Other items	(277,000)	(1,974,000)
Changes in working capital items:
(Increase) decrease in current assets	(2,851,000)	14,089,000
(Decrease) increase in current liabilities	(4,213,000)	(2,738,000)
Dividends from investments	1,967,000	2,700,000
Cash contributions to pension and other postretirement plans	(1,552,000)	(1,470,000)
Other noncurrent items, net	(1,115,000)	47,000
Cash Provided by Operating Activities	43,883,000	53,819,000
Investing Activities:
Capital expenditures	(34,746,000)	(46,758,000)
Capital contributions to investments	(670,000)	(1,643,000)
Other	(419,000)	(398,000)
Cash Used for Investing Activities	(35,835,000)	(48,799,000)
Financing Activities:
Cash dividends paid on common stock	(13,380,000)	(12,221,000)
Repayments of long-term debt	(1,182,000)	(1,155,000)
Net proceeds from short-term debt	1,500,000	3,000,000
Other	(523,000)	(664,000)
Cash Used for Financing Activities	(13,585,000)	(11,040,000)
Change in cash, cash equivalents, and restricted cash	(5,537,000)	(6,020,000)
Cash, cash equivalents, and restricted cash at beginning of period	47,039,000	25,814,000
Cash, cash equivalents, and restricted cash at end of period	41,502,000	19,794,000
Significant noncash investing activities:
Accrued capital expenditures	8,843,000	8,129,000
MGE [Member]
Operating Activities:
Net Income	33,774,000	24,557,000
Items not affecting cash:
Depreciation and amortization	18,382,000	18,167,000
Deferred income taxes	(1,766,000)	976,000
Provision for doubtful receivables	388,000	734,000
Employee benefit plan cost (credit)	1,461,000	(940,000)
Other items	(252,000)	(1,721,000)
Changes in working capital items:
(Increase) decrease in current assets	(3,037,000)	12,953,000
(Decrease) increase in current liabilities	(4,037,000)	290,000
Cash contributions to pension and other postretirement plans	(1,552,000)	(1,470,000)
Other noncurrent items, net	(1,380,000)	(428,000)
Cash Provided by Operating Activities	41,981,000	53,118,000
Investing Activities:
Capital expenditures	(34,746,000)	(46,758,000)
Other	(462,000)	(406,000)
Cash Used for Investing Activities	(35,208,000)	(47,164,000)
Financing Activities:
Distributions to parent from noncontrolling interest	(5,000,000)	(7,000,000)
Repayments of long-term debt	(1,182,000)	(1,155,000)
Net proceeds from short-term debt	1,500,000	3,000,000
Other	(523,000)	(664,000)
Cash Used for Financing Activities	(5,205,000)	(5,819,000)
Change in cash, cash equivalents, and restricted cash	1,568,000	135,000
Cash, cash equivalents, and restricted cash at beginning of period	6,404,000	5,529,000
Cash, cash equivalents, and restricted cash at end of period	7,972,000	5,664,000
Significant noncash investing activities:
Accrued capital expenditures	$ 8,843,000	$ 8,129,000