MGE Energy Inc Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Comprehensive Income [Abstract]
Net Income	$ 26,629	$ 27,880	$ 61,472	$ 61,058
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	60	11	189	(143)
Comprehensive Income	$ 26,689	$ 27,891	$ 61,661	$ 60,915

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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