Unaudited Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Unaudited Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 4,907	$ 4,050	$ 19,850	$ 15,556
Unrealized net gains (losses) on securities:
Unrealized net gains (losses) arising during the period	(1,024)	(4,635)	6,779	3,003
Less: reclassification adjustment for net gains (losses) included in net income	1,296	(370)	8,208	(397)
Change in unrealized gains (losses) on investments	(2,320)	(4,265)	(1,429)	3,400
Foreign currency translation adjustments	(294)	(223)	(481)	(19)
Other comprehensive income (loss)	(2,614)	(4,488)	(1,910)	3,381
Comprehensive income (loss)	$ 2,293	$ (438)	$ 17,940	$ 18,937