Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating Activities:
Net Income	$ 92,701	$ 76,622
Items not affecting cash:
Depreciation and amortization	55,968	55,193
Deferred income taxes	1,955	8,464
Provision for doubtful receivables	1,163	1,078
Employee benefit plan cost (credit)	(935)	(2,813)
Equity earnings in investments	(7,440)	(7,780)
Other items	(618)	382
Changes in working capital items:
(Increase) decrease in current assets	(11,240)	5,494
Increase (decrease) in current liabilities	4,429	(8,808)
Dividends from investments	5,842	6,929
Cash contributions to pension and other postretirement plans	(4,823)	(4,576)
Other noncurrent items, net	4,295	5,826
Cash Provided by Operating Activities	141,297	136,011
Investing Activities:
Capital expenditures	(114,142)	(139,055)
Capital contributions to investments	(4,227)	(4,007)
Other	22	(1,298)
Cash Used for Investing Activities	(118,347)	(144,360)
Financing Activities:
Issuance of common stock, net	0	79,635
Cash dividends paid on common stock	(40,774)	(38,349)
Repayments of long-term debt	(3,567)	(22,784)
Issuance of long-term debt	100,000	19,300
Net repayments of short-term debt	(52,500)	0
Other	(1,503)	(1,175)
Cash Provided by Financing Activities	1,656	36,627
Change in cash, cash equivalents, and restricted cash	24,606	28,278
Cash, cash equivalents, and restricted cash at beginning of period	47,039	25,814
Cash, cash equivalents, and restricted cash at end of period	71,645	54,092
Significant noncash investing activities:
Accrued capital expenditures	8,213	23,594
MGE [Member]
Operating Activities:
Net Income	87,529	71,191
Items not affecting cash:
Depreciation and amortization	55,968	55,193
Deferred income taxes	1,375	7,334
Provision for doubtful receivables	1,163	1,078
Employee benefit plan cost (credit)	(935)	(2,813)
Other items	(864)	1,234
Changes in working capital items:
(Increase) decrease in current assets	(11,777)	3,352
Increase (decrease) in current liabilities	2,528	(5,212)
Cash contributions to pension and other postretirement plans	(4,823)	(4,576)
Other noncurrent items, net	3,559	5,090
Cash Provided by Operating Activities	135,451	131,871
Investing Activities:
Capital expenditures	(114,142)	(139,055)
Other	(1,449)	(1,512)
Cash Used for Investing Activities	(115,591)	(140,567)
Financing Activities:
Distributions to parent from noncontrolling interest	(10,500)	(16,000)
Capital contributions from parent	0	30,000
Repayments of long-term debt	(3,567)	(22,784)
Issuance of long-term debt	100,000	19,300
Net repayments of short-term debt	(52,500)	0
Other	(1,503)	(1,144)
Cash Provided by Financing Activities	31,930	9,372
Change in cash, cash equivalents, and restricted cash	51,790	676
Cash, cash equivalents, and restricted cash at beginning of period	6,404	5,529
Cash, cash equivalents, and restricted cash at end of period	58,194	6,205
Significant noncash investing activities:
Accrued capital expenditures	$ 8,213	$ 23,594