Consolidated Statements of Comprehensive Income (Unaudited) (Parantheticals) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale securities, taxes	$ (5)	$ (50)	$ 24	$ 4
Reclassification of realized gain on available-for-sale securities, taxes	0	0	0	(10)
MGE [Member]
Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale securities, taxes	(5)	(35)	(20)	(14)
Reclassification of realized gain on available-for-sale securities, taxes	$ 0	$ 0	$ 0	$ (10)