MGE Energy Inc Consolidated Statements of Common Equity (USD $) In Thousands, unless otherwise specified		Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss)/ Income [Member]	Comprehensive Income [Member]
Beginning balance, value at Dec. 31, 2008		$ 478,202	$ 22,905	$ 310,202	$ 144,904	$ 191
Beginning balance, shares at Dec. 31, 2008			22,905
Net Income		50,997			50,997		50,997
Other comprehensive income/(loss):
Net unrealized gain (loss) on investments, net of tax	[1]	14				14	14
Total comprehensive income							51,011
Common stock dividends declared	[2]	(33,693)			(33,693)
Common stock issued during period			209
Common stock issued, net value		6,275	209	6,066
Ending balance, value at Dec. 31, 2009		501,795	23,114	316,268	162,208	205
Ending balance, shares at Dec. 31, 2009			23,114
Net Income		57,718			57,718		57,718
Other comprehensive income/(loss):
Net unrealized gain (loss) on investments, net of tax	[3]	(63)				(63)	(63)
Total comprehensive income							57,655
Common stock dividends declared	[4]	(34,370)			(34,370)
Ending balance, value at Dec. 31, 2010		525,080	23,114	316,268	185,556	142
Ending balance, shares at Dec. 31, 2010			23,114
Net Income		60,928			60,928		60,928
Other comprehensive income/(loss):
Net unrealized gain (loss) on investments, net of tax	[1]	(15)				(15)	(15)
Reclassification of realized gain on available-for-sale securities, net of tax	[1]	(15)				(15)	(15)
Total comprehensive income							60,898
Common stock dividends declared	[5]	(35,026)			(35,026)
Ending balance, value at Dec. 31, 2011		$ 550,952	$ 23,114	$ 316,268	$ 211,458	$ 112
Ending balance, shares at Dec. 31, 2011			23,114

[1] net of $10 tax

[2] $1.46 per share

[3] net of $42 tax

[4] $1.49 per share

[5] $1.52 per share