Goodwill and Intangible Assets, Net, Carrying Amount of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Goodwill
Balance at the beginning of the period			$ 137,140
Reclassifications			0
Foreign exchange			(742)
Balance at the end of the period	$ 136,398	$ 137,160	136,398	$ 137,160
Intangible Assets
Balance at the beginning of the period			29,326
Reclassifications			220
Amortization	(1,300)	(1,700)	(2,627)	(3,200)
Foreign exchange			(158)
Balance at the end of the period	$ 26,761	$ 30,804	$ 26,761	$ 30,804