Unaudited Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Unaudited Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 9,340	$ 4,907	$ 15,701	$ 19,850
Unrealized net gains (losses) on securities:
Unrealized net gains (losses) arising during the period	6,994	(1,024)	12,829	6,779
Less: reclassification adjustment for net gains (losses) included in net income	1,877	1,296	2,529	8,208
Change in unrealized gains (losses) on investments	5,117	(2,320)	10,300	(1,429)
Foreign currency translation adjustments	371	(294)	(130)	(481)
Other comprehensive income (loss)	5,488	(2,614)	10,170	(1,910)
Comprehensive income	$ 14,828	$ 2,293	$ 25,871	$ 17,940