Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Other Comprehensive Income [Abstract]
Unrealized gains on available-for-sale securities, taxes	$ (562)	$ (2,155)	$ (730)	$ (2,647)
Other Comprehensive Income Loss Reclassification Adjustment For Sale Or Writedown Of Securities Included In Net Income Tax	171	52	321	51
Unrealized gains (losses) on available-for-sale securities for which a portion of an other-than-temporary impairment has been recognized in income, taxes	$ 2	$ 18	$ 0	$ 0