Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Other Comprehensive Income [Abstract]
Unrealized gains on available-for-sale securities, taxes	$ (329)	$ (1,066)	$ 6,432	$ (1,796)
Other Comprehensive Income Loss Reclassification Adjustment For Sale Or Writedown Of Securities Included In Net Income Tax	567	43	893	364
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Income (Loss), Tax, Including Portion Attributable to Noncontrolling Interest, Available-for-sale Securities	$ 0	$ 0	$ 0	$ 0