Unaudited Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Unaudited Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 7,434	$ 4,001	$ 1,847	$ 24,082
Unrealized net gains (losses) on securities:
Unrealized net gains arising during the period	4,862	4,900	15,999	7,471
Less: reclassification adjustment for net gains included in net income	2,240	2,164	4,562	8,985
Change in unrealized gains (losses) on investments	2,622	2,736	11,437	(1,514)
Foreign currency translation adjustments	57	(145)	510	398
Other comprehensive income (loss)	2,679	2,591	11,947	(1,116)
Comprehensive income	$ 10,113	$ 6,592	$ 13,794	$ 22,966