Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 97,331	$ 81,384
Accounts receivable, less reserves	36,710	37,112
Other accounts receivables, less reserves	5,637	7,477
Unbilled revenues	23,375	25,008
Materials and supplies, at average cost	20,335	19,155
Fossil fuel	10,222	13,110
Stored natural gas, at average cost	8,548	16,145
Prepaid taxes	24,606	35,252
Regulatory assets - current	10,448	9,538
Other current assets	9,992	10,570
Total Current Assets	247,204	254,751
Regulatory assets	149,987	148,199
Other deferred assets and other	6,476	6,377
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,218,282	1,217,094
Construction work in progress	33,198	26,351
Total Property, Plant, and Equipment	1,251,480	1,243,445
Investments	75,269	73,631
Total Assets	1,730,416	1,726,403
Current Liabilities:
Long-term debt due within one year	34,264	4,266
Accounts payable	41,132	40,830
Accrued interest and taxes	3,975	5,067
Accrued payroll related items	8,926	11,215
Regulatory liabilities - current	11,071	9,515
Derivative liabilities	9,374	8,343
Other current liabilities	9,181	4,910
Total Current Liabilities	117,923	84,146
Other Credits:
Deferred income taxes	363,671	360,785
Investment tax credit - deferred	1,024	1,050
Regulatory liabilities	21,493	20,785
Accrued pension and other postretirement benefits	64,259	75,680
Derivative liabilities	46,540	44,935
Other deferred liabilities and other	62,620	61,820
Total Other Credits	559,607	565,055
Capitalization:
Common shareholders equity	697,095	690,458
Long-term debt	355,791	386,744
Total Capitalization	$ 1,052,886	$ 1,077,202
Commitments and contingencies (see Footnote 7)
Total Liabilities and Capitalization	$ 1,730,416	$ 1,726,403
MGE [Member]
Current Assets:
Cash and cash equivalents	36,809	26,760
Accounts receivable, less reserves	36,710	37,112
Affiliate receivables	686	542
Other accounts receivables, less reserves	5,522	7,390
Unbilled revenues	23,375	25,008
Materials and supplies, at average cost	20,335	19,155
Fossil fuel	10,222	13,110
Stored natural gas, at average cost	8,547	16,145
Prepaid taxes	23,764	34,279
Regulatory assets - current	10,448	9,538
Other current assets	9,978	10,544
Total Current Assets	186,396	199,583
Affiliate receivable long-term	4,633	4,766
Regulatory assets	149,987	148,199
Other deferred assets and other	4,219	4,216
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,217,614	1,216,415
Construction work in progress	33,198	26,351
Total Property, Plant, and Equipment	1,250,812	1,242,766
Investments	71,835	69,984
Total Assets	1,667,882	1,669,514
Current Liabilities:
Long-term debt due within one year	34,264	4,266
Accounts payable	41,140	40,742
Accrued interest and taxes	3,927	5,021
Accrued payroll related items	8,926	11,215
Regulatory liabilities - current	11,071	9,515
Derivative liabilities	9,374	8,343
Other current liabilities	9,005	4,791
Total Current Liabilities	117,707	83,893
Other Credits:
Deferred income taxes	355,264	352,626
Investment tax credit - deferred	1,024	1,050
Regulatory liabilities	21,493	20,785
Accrued pension and other postretirement benefits	64,259	75,680
Derivative liabilities	46,540	44,935
Other deferred liabilities and other	62,620	61,817
Total Other Credits	551,200	556,893
Capitalization:
Common shareholders equity	502,591	501,676
Noncontrolling interest	140,593	140,308
Total Equity	643,184	641,984
Long-term debt	355,791	386,744
Total Capitalization	$ 998,975	$ 1,028,728
Commitments and contingencies (see Footnote 7)
Total Liabilities and Capitalization	$ 1,667,882	$ 1,669,514