MGE Energy Inc Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Comprehensive Income [Abstract]
Net Income	$ 27,880	$ 28,354	$ 61,058	$ 60,111
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	11	(85)	(143)	(180)
Comprehensive Income	$ 27,891	$ 28,269	$ 60,915	$ 59,931