Consolidated Statements of Comprehensive Income (Unaudited) (Parantheticals) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale securities, taxes	$ 24	$ 6	$ 29	$ 54
Reclassification of realized gain on available-for-sale securities, taxes	0	(10)	0	(10)
MGE [Member]
Comprehensive Income [Abstract]
Unrealized gain (loss) on available-for-sale securities, taxes	(5)	(2)	(15)	21
Reclassification of realized gain on available-for-sale securities, taxes	$ 0	$ (10)	$ 0	$ (10)