Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current Assets:
Cash and cash equivalents	$ 133,855	$ 107,952
Accounts receivable, less reserves	41,693	42,299
Other accounts receivables, less reserves	7,565	9,440
Unbilled revenues	20,979	31,400
Materials and supplies, at average cost	24,869	22,614
Fuel for electric generation, at average cost	6,945	8,256
Stored natural gas, at average cost	13,614	12,923
Prepaid taxes	12,239	26,535
Regulatory assets - current	8,739	7,888
Assets held for sale	1,755	8,817
Other current assets	8,459	12,507
Total Current Assets	280,712	290,631
Other long-term receivables	3,747	4,788
Regulatory assets	133,936	142,567
Pension and other postretirement benefit asset	14,266	7,336
Other deferred assets and other	8,729	731
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,350,253	1,283,313
Construction work in progress	109,209	58,044
Total Property, Plant, and Equipment	1,459,462	1,341,357
Investments	73,445	67,772
Total Assets	1,974,297	1,855,182
Current Liabilities:
Long-term debt due within one year	4,527	24,452
Short-term debt	0	4,000
Accounts payable	50,340	47,645
Accrued interest and taxes	5,554	5,602
Accrued payroll related items	10,879	12,244
Regulatory liabilities - current	7,330	5,633
Derivative liabilities	9,350	8,180
Other current liabilities	10,509	18,758
Total Current Liabilities	98,489	126,514
Other Credits:
Deferred income taxes	229,197	225,130
Investment tax credit - deferred	843	918
Regulatory liabilities	171,057	154,153
Accrued pension and other postretirement benefits	69,346	69,088
Derivative liabilities	26,920	33,990
Other deferred liabilities and other	72,064	69,041
Total Other Credits	569,427	552,320
Capitalization:
Common shareholders equity	811,983	778,187
Long-term debt	494,398	398,161
Total Capitalization	1,306,381	1,176,348
Commitments and contingencies (see Footnote 9)
Total Liabilities and Capitalization	1,974,297	1,855,182
MGE [Member]
Current Assets:
Cash and cash equivalents	47,264	5,951
Accounts receivable, less reserves	41,693	42,299
Affiliate receivables	686	668
Other accounts receivables, less reserves	5,856	6,984
Unbilled revenues	20,979	31,400
Materials and supplies, at average cost	24,869	22,614
Fuel for electric generation, at average cost	6,945	8,256
Stored natural gas, at average cost	13,614	12,923
Prepaid taxes	11,486	25,073
Regulatory assets - current	8,739	7,888
Assets held for sale	1,755	8,817
Other current assets	8,424	12,484
Total Current Assets	192,310	185,357
Affiliate receivable long-term	3,310	3,707
Regulatory assets	133,936	142,567
Pension and other postretirement benefit asset	14,266	7,336
Other deferred assets and other	10,517	3,280
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,350,281	1,283,341
Construction work in progress	109,209	58,044
Total Property, Plant, and Equipment	1,459,490	1,341,385
Investments	415	409
Total Assets	1,814,244	1,684,041
Current Liabilities:
Long-term debt due within one year	4,527	24,452
Short-term debt	0	4,000
Accounts payable	50,315	47,614
Accrued interest and taxes	7,409	5,558
Accrued payroll related items	10,879	12,244
Regulatory liabilities - current	7,330	5,633
Derivative liabilities	9,350	8,180
Other current liabilities	10,509	16,749
Total Current Liabilities	100,319	124,430
Other Credits:
Deferred income taxes	202,748	201,486
Investment tax credit - deferred	843	918
Regulatory liabilities	171,057	154,153
Accrued pension and other postretirement benefits	69,346	69,088
Derivative liabilities	26,920	33,990
Other deferred liabilities and other	72,064	69,041
Total Other Credits	542,978	528,676
Capitalization:
Common shareholders equity	537,707	491,872
Noncontrolling interest	138,842	140,902
Total Equity	676,549	632,774
Long-term debt	494,398	398,161
Total Capitalization	1,170,947	1,030,935
Commitments and contingencies (see Footnote 9)
Total Liabilities and Capitalization	$ 1,814,244	$ 1,684,041