Condensed 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
Statement of Comprehensive Income [Abstract]
Net income	$ 3,454	$ 17,662	$ 11,000	$ 25,000
Net unrealized investment gains (losses):
Unrealized holding gains (losses), net of tax provisions of less than $0.1 and $0.2 million for the three and nine months ended September 30, 2017, respectively, and tax benefit of $0.2 million and tax provision of $0.5 million for the three and nine months ended September 30, 2016, respectively	48	(316)	283	785
Reclassification adjustments included in net income, net of tax benefit and tax provision of less than $0.1 million for the three and nine months ended September 30, 2017, and tax benefit and tax provision of less than $0.1 million for the three and nine months ended September 30, 2016, respectively	(27)	(98)	(49)	16
Net unrealized investment gains (losses)	21	(414)	234	801
Currency translation adjustments, net of no tax benefit for the three and nine months ended September 30, 2017, and tax provisions of $0.4 and $0.7 million for the three and nine months ended September 30, 2016, respectively	4,931	1,509	23,121	3,293
Net unrealized gains (losses) on cash flow hedges	(28)	27	(24)	11
Comprehensive income	$ 8,378	$ 18,784	$ 34,331	$ 29,105