Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 70,454	$ 44,738
Accounts receivable, less reserves	43,162	41,384
Other accounts receivables, less reserves	12,950	7,300
Unbilled revenues	22,973	27,511
Materials and supplies, at average cost	31,179	32,513
Fuel for electric generation, at average cost	3,724	6,356
Stored natural gas, at average cost	15,624	8,396
Prepaid taxes	12,983	15,179
Regulatory assets - current	8,060	14,748
Other current assets	12,976	11,394
Total Current Assets	234,085	209,519
Other long-term receivables	982	1,435
Regulatory assets	135,603	142,504
Pension benefit asset	25,594	13,873
Other deferred assets and other	27,868	22,259
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,743,447	1,630,286
Construction work in progress	103,919	139,099
Total Property, Plant, and Equipment	1,847,366	1,769,385
Investments	99,236	94,676
Total Assets	2,370,734	2,253,651
Current Liabilities:
Long-term debt due within one year	4,859	4,771
Short-term debt	0	52,500
Accounts payable	57,431	54,642
Accrued interest and taxes	7,769	8,539
Accrued payroll related items	12,109	12,635
Regulatory liabilities - current	31,293	41,664
Derivative liabilities	160	10,160
Other current liabilities	9,922	6,015
Total Current Liabilities	123,543	190,926
Other Credits:
Deferred income taxes	241,731	231,471
Investment tax credit - deferred	31,011	21,821
Regulatory liabilities	149,028	142,239
Accrued pension and other postretirement benefits	77,406	78,168
Derivative liabilities	0	3,980
Finance lease liabilities	17,828	17,532
Other deferred liabilities and other	86,591	72,211
Total Other Credits	603,595	567,422
Capitalization:
Common shareholders equity	1,028,285	976,000
Long-term debt	615,311	519,303
Total Capitalization	1,643,596	1,495,303
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	2,370,734	2,253,651
MGE [Member]
Current Assets:
Cash and cash equivalents	57,003	4,103
Accounts receivable, less reserves	43,162	41,384
Affiliate receivables	532	532
Other accounts receivables, less reserves	12,947	7,295
Unbilled revenues	22,973	27,511
Materials and supplies, at average cost	31,179	32,513
Fuel for electric generation, at average cost	3,724	6,356
Stored natural gas, at average cost	15,624	8,396
Prepaid taxes	13,210	14,848
Regulatory assets - current	8,060	14,748
Other current assets	12,884	11,326
Total Current Assets	221,298	169,012
Affiliate receivable long-term	1,721	2,118
Regulatory assets	135,603	142,504
Pension benefit asset	25,594	13,873
Other deferred assets and other	27,839	22,448
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,743,475	1,630,314
Construction work in progress	103,919	139,099
Total Property, Plant, and Equipment	1,847,394	1,769,413
Investments	244	603
Total Assets	2,259,693	2,119,971
Current Liabilities:
Long-term debt due within one year	4,859	4,771
Short-term debt	0	52,500
Accounts payable	57,404	54,576
Accrued interest and taxes	7,723	10,405
Accrued payroll related items	12,109	12,635
Regulatory liabilities - current	31,293	41,664
Derivative liabilities	160	10,160
Other current liabilities	9,922	6,042
Total Current Liabilities	123,470	192,753
Other Credits:
Deferred income taxes	210,071	200,390
Investment tax credit - deferred	31,011	21,821
Regulatory liabilities	149,028	142,239
Accrued pension and other postretirement benefits	77,406	78,168
Derivative liabilities	0	3,980
Finance lease liabilities	17,828	17,532
Other deferred liabilities and other	86,927	72,173
Total Other Credits	572,271	536,303
Capitalization:
Common shareholders equity	801,190	730,416
Noncontrolling interest	147,451	141,196
Total Equity	948,641	871,612
Long-term debt	615,311	519,303
Total Capitalization	1,563,952	1,390,915
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	$ 2,259,693	$ 2,119,971