MGE Energy Inc Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Comprehensive Income [Abstract]
Net Income	$ 23,329	$ 24,353	$ 65,133	$ 60,828
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	95	36	56	176
Comprehensive Income	$ 23,424	$ 24,389	$ 65,189	$ 61,004