MGE Energy Inc Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Comprehensive Income [Abstract]
Net Income	$ 15,543	$ 16,150	$ 34,843	$ 33,178
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	32	10	129	(154)
Comprehensive Income	$ 15,575	$ 16,160	$ 34,972	$ 33,024