Unaudited Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Unaudited Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 5,770	$ 7,771	$ 21,471	$ 27,621
Unrealized net gains (losses) on securities:
Unrealized net gains (losses) arising during the period	(3,472)	6,921	9,358	13,699
Less: reclassification adjustment for net gains (losses) included in net income	1,118	1,068	3,648	9,275
Change in unrealized gains (losses) on investments	(4,590)	5,853	5,710	4,424
Foreign currency translation adjustments	(705)	199	(835)	(282)
Other comprehensive income (loss)	(5,295)	6,052	4,875	4,142
Comprehensive income	$ 475	$ 13,823	$ 26,346	$ 31,763