Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current Assets:
Cash and cash equivalents	$ 88,719	$ 68,813
Accounts receivable, less reserves	35,251	44,890
Other accounts receivables, less reserves	5,365	5,352
Unbilled revenues	19,929	31,982
Materials and supplies, at average cost	17,524	16,662
Fossil fuel	5,121	5,206
Stored natural gas, at average cost	23,292	13,988
Prepaid taxes	15,569	19,106
Regulatory assets - current	4,985	6,377
Other current assets	9,650	8,225
Total Current Assets	225,405	220,601
Regulatory assets	100,227	107,166
Pension benefits	17,942	15,071
Other deferred assets and other	7,029	8,046
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,176,592	1,018,809
Construction work in progress	21,331	141,415
Total Property, Plant, and Equipment	1,197,923	1,160,224
Investments	71,370	67,952
Total Assets	1,619,896	1,579,060
Current Liabilities:
Long-term debt due within one year	4,162	4,102
Accounts payable	41,871	43,684
Accrued interest and taxes	4,041	5,661
Accrued payroll related items	10,305	10,731
Deferred income taxes	0	1,711
Regulatory liabilities - current	8,822	13,538
Derivative liabilities	7,131	7,750
Other current liabilities	5,824	9,489
Total Current Liabilities	82,156	96,666
Other Credits:
Deferred income taxes	313,101	284,791
Investment tax credit - deferred	1,274	1,413
Regulatory liabilities	21,970	19,792
Accrued pension and other postretirement benefits	50,339	49,184
Derivative liabilities	47,820	57,930
Other deferred liabilities and other	52,947	52,360
Total Other Credits	487,451	465,470
Capitalization:
Common shareholders equity	653,985	617,510
Long-term debt	396,304	399,414
Total Capitalization	1,050,289	1,016,924
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	1,619,896	1,579,060
MGE [Member]
Current Assets:
Cash and cash equivalents	22,983	14,808
Accounts receivable, less reserves	35,251	44,890
Affiliate receivables	609	534
Other accounts receivables, less reserves	5,290	5,274
Unbilled revenues	19,929	31,982
Materials and supplies, at average cost	17,524	16,662
Fossil fuel	5,121	5,206
Stored natural gas, at average cost	23,292	13,988
Prepaid taxes	20,390	23,934
Regulatory assets - current	4,985	6,377
Other current assets	9,546	8,197
Total Current Assets	164,920	171,852
Affiliate receivable long-term	5,428	5,825
Regulatory assets	100,227	107,166
Pension benefits	17,942	15,071
Other deferred assets and other	4,987	6,138
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,175,695	1,017,877
Construction work in progress	21,331	141,415
Total Property, Plant, and Equipment	1,197,026	1,159,292
Investments	68,172	65,299
Total Assets	1,558,702	1,530,643
Current Liabilities:
Long-term debt due within one year	4,162	4,102
Accounts payable	41,861	43,684
Accrued interest and taxes	3,774	6,040
Accrued payroll related items	10,305	10,731
Deferred income taxes	1,143	2,723
Regulatory liabilities - current	8,822	13,538
Derivative liabilities	7,131	7,750
Other current liabilities	5,495	6,446
Total Current Liabilities	82,693	95,014
Other Credits:
Deferred income taxes	306,559	279,085
Investment tax credit - deferred	1,274	1,413
Regulatory liabilities	21,970	19,792
Accrued pension and other postretirement benefits	50,338	49,184
Derivative liabilities	47,820	57,930
Other deferred liabilities and other	52,947	52,357
Total Other Credits	480,908	459,761
Capitalization:
Common shareholders equity	476,408	457,491
Noncontrolling interest	122,389	118,963
Total Equity	598,797	576,454
Long-term debt	396,304	399,414
Total Capitalization	995,101	975,868
Commitments and contingencies (see Footnote 8)
Total Liabilities and Capitalization	$ 1,558,702	$ 1,530,643