Income Taxes - Significant Components of Income Tax Provision/(Benefit) (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
U.S.	$ 1,635	$ (1,312)	$ 329
Non-U.S.	7,150	13,729	12,482
Total Current	8,785	12,417	12,811
Deferred:
U.S.	17,597	13,245	(15,795)
Non-U.S.	(577)	(2,797)	8,291
Total Deferred	17,020	10,448	(7,504)
Total provision for income taxes	$ 25,805	$ 22,865	$ 5,307