MGE Energy Inc Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Comprehensive Income [Abstract]
Net Income	$ 18,351	$ 15,543	$ 38,352	$ 34,843
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	0	32	0	129
Comprehensive Income	$ 18,351	$ 15,575	$ 38,352	$ 34,972

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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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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

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