Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating Activities:
Net Income	$ 44,828	$ 39,554
Items not affecting cash:
Depreciation and amortization	36,601	35,230
Deferred income taxes	5,088	2,306
Provision for doubtful receivables	817	732
Employee benefit plan credit	(1,875)	(1,920)
Equity earnings in ATC	(5,405)	(4,515)
Other items	(1,006)	(717)
Changes in working capital items:
Decrease in current assets	9,934	15,349
(Decrease) increase in current liabilities	(8,195)	(951)
Dividends from ATC	4,581	3,745
Cash contributions to pension and other postretirement plans	(2,943)	(2,319)
Other noncurrent items, net	3,025	(610)
Cash Provided by Operating Activities	85,450	85,884
Investing Activities:
Capital expenditures	(85,217)	(79,092)
Capital contributions to investments	(2,577)	(3,386)
Other	(899)	(156)
Cash Used for Investing Activities	(88,693)	(82,634)
Financing Activities:
Issuance of common stock, net	79,635	0
Cash dividends paid on common stock	(24,968)	(23,401)
Repayments of long-term debt	(21,616)	(2,263)
Issuance of long-term debt	19,300	0
Net proceeds from short-term debt	0	10,500
Other	(1,030)	(1,193)
Cash Provided by (Used for) Financing Activities	51,321	(16,357)
Change in cash, cash equivalents, and restricted cash	48,078	(13,107)
Cash, cash equivalents, and restricted cash at beginning of period	25,814	84,929
Cash, cash equivalents, and restricted cash at end of period	73,892	71,822
Significant noncash investing activities:
Accrued capital expenditures	15,762	2,264
MGE [Member]
Operating Activities:
Net Income	40,958	36,013
Items not affecting cash:
Depreciation and amortization	36,601	35,230
Deferred income taxes	4,034	1,231
Provision for doubtful receivables	817	732
Employee benefit plan credit	(1,875)	(1,920)
Other items	(380)	(181)
Changes in working capital items:
Decrease in current assets	7,460	15,845
(Decrease) increase in current liabilities	(4,439)	1,096
Cash contributions to pension and other postretirement plans	(2,943)	(2,319)
Other noncurrent items, net	2,412	(441)
Cash Provided by Operating Activities	82,645	85,286
Investing Activities:
Capital expenditures	(85,217)	(79,092)
Other	(890)	(271)
Cash Used for Investing Activities	(86,107)	(79,363)
Financing Activities:
Distributions to parent from noncontrolling interest	(8,500)	(11,500)
Capital contributions from parent	30,000	0
Repayments of long-term debt	(21,616)	(2,263)
Issuance of long-term debt	19,300	0
Net proceeds from short-term debt	0	10,500
Other	(999)	(1,038)
Cash Provided by (Used for) Financing Activities	18,185	(4,301)
Change in cash, cash equivalents, and restricted cash	14,723	1,622
Cash, cash equivalents, and restricted cash at beginning of period	5,529	6,670
Cash, cash equivalents, and restricted cash at end of period	20,252	8,292
Significant noncash investing activities:
Accrued capital expenditures	$ 15,762	$ 2,264