Income Taxes - Schedule of Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
U.S.	$ 8,491	$ 6,501	$ 891
Non-U.S.	5,028	3,863	3,678
Total current	13,519	10,364	4,569
Deferred:
U.S.	(3)	1
Non-U.S.	(351)	16	(135)
Total deferred	(354)	17	(135)
Total income taxes provision	$ 13,165	$ 10,381	$ 4,434