Consolidated Balance Sheets (Unaudited) (USD $) In Thousands	Jun. 30, 2011		Dec. 31, 2010
MGE Energy [Member]
Current Assets:
Cash and cash equivalents	$ 32,054		$ 7,110
Receivable - margin account	3,682		2,501
Accounts receivable, less reserves	32,364	[1]	40,153	[2]
Other accounts receivables, less reserves	4,734	[3]	4,082	[4]
Unbilled revenues	21,019		29,220
Materials and supplies, at average cost	17,293		17,642
Fossil fuel	7,097		6,758
Stored natural gas, at average cost	13,706		22,839
Prepaid taxes	17,000		22,496
Regulatory assets - current	732		1,732
Other current assets	8,083		7,769
Total Current Assets	157,764		162,302
Regulatory assets	124,098		121,085
Other deferred assets and other	10,229		10,654
Property, Plant, and Equipment:
Property, plant, and equipment, net	943,081		857,572
Construction work in progress	35,987		110,435
Total Property, Plant, and Equipment	979,068		968,007
Investments	59,255		55,845
Total Assets	1,330,414		1,317,893
Current Liabilities:
Long-term debt due within one year	2,667		1,667
Short-term debt	0		22,500
Accounts payable	25,691		32,555
Accrued interest and taxes	4,141		3,990
Accrued payroll related items	8,327		8,525
Deferred income taxes	2,479		2,398
Other current liabilities	8,949		9,577
Total Current Liabilities	52,254		81,212
Other Credits:
Deferred income taxes	176,254		166,774
Investment tax credit - deferred	1,931		2,081
Regulatory liabilities	21,381		23,772
Accrued pension and other postretirement benefits	108,022		123,648
Other deferred liabilities and other	70,050		60,975
Total Other Credits	377,638		377,250
Capitalization:
Common shareholders equity	538,312		525,080
Long-term debt	362,210		334,351
Total Capitalization	900,522		859,431
Commitments and contingencies (see Footnote 9)	0		0
Total Liabilities and Capitalization	1,330,414		1,317,893
MGE [Member]
Current Assets:
Cash and cash equivalents	17,248		4,494
Receivable - margin account	3,682		2,501
Accounts receivable, less reserves	32,364	[1]	40,153	[2]
Affiliate receivables	537		638
Other accounts receivables, less reserves	4,716	[3]	4,063	[4]
Unbilled revenues	21,019		29,220
Materials and supplies, at average cost	17,293		17,642
Fossil fuel	7,097		6,758
Stored natural gas, at average cost	13,706		22,839
Prepaid taxes	16,340		21,500
Regulatory assets - current	732		1,732
Other current assets	8,075		7,742
Total Current Assets	142,809		159,282
Affiliate receivable long-term	7,148		7,413
Regulatory assets	124,098		121,085
Other deferred assets and other	7,416		8,337
Property, Plant, and Equipment:
Property, plant, and equipment, net	942,942		857,442
Construction work in progress	35,987		110,435
Total Property, Plant, and Equipment	978,929		967,877
Investments	56,427		54,947
Total Assets	1,316,827		1,318,941
Current Liabilities:
Long-term debt due within one year	2,667		1,667
Short-term debt	0		3,500
Accounts payable	25,691		32,524
Affiliate payables	2,718		24
Accrued interest and taxes	4,093		7,294
Accrued payroll related items	8,327		8,525
Deferred income taxes	2,479		2,398
Other current liabilities	8,413		9,472
Total Current Liabilities	54,388		65,404
Other Credits:
Deferred income taxes	173,410		164,399
Investment tax credit - deferred	1,931		2,081
Regulatory liabilities	21,381		23,772
Accrued pension and other postretirement benefits	108,022		123,648
Other deferred liabilities and other	70,051		60,977
Total Other Credits	374,795		374,877
Capitalization:
Common shareholders equity	407,894		402,316
Noncontrolling interest	117,540		141,993
Total Equity	525,434		544,309
Long-term debt	362,210		334,351
Total Capitalization	887,644		878,660
Commitments and contingencies (see Footnote 9)	0		0
Total Liabilities and Capitalization	$ 1,316,827		$ 1,318,941

[1] less reserves of $4,094

[2] less reserves of $3,994

[3] less reserves of $476

[4] less reserves of $595