Goodwill Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Goodwill Roll Forward
Goodwill, Beginning Balance	$ 80,804	$ 79,111
Goodwill Additions	1,832	3,197
Goodwill, Translation Adjustments	3,398	(1,504)
Goodwill, Ending Balance	86,034	80,804
North America [Member]
Goodwill Roll Forward
Goodwill, Beginning Balance	45,490	42,443
Goodwill Additions	1,832	3,311
Goodwill, Translation Adjustments	249	(264)
Goodwill, Ending Balance	47,571	45,490
EMEA [Member]
Goodwill Roll Forward
Goodwill, Beginning Balance	18,189	19,280
Goodwill Additions	0
Goodwill Reductions		(114)
Goodwill, Translation Adjustments	2,315	(977)
Goodwill, Ending Balance	20,504	18,189
Asia Pacific [Member]
Goodwill Roll Forward
Goodwill, Beginning Balance	14,566	15,244
Goodwill Additions	0	0
Goodwill, Translation Adjustments	890	(678)
Goodwill, Ending Balance	15,456	14,566
South America [Member]
Goodwill Roll Forward
Goodwill, Beginning Balance	2,559	2,144
Goodwill Additions	0	0
Goodwill, Translation Adjustments	(56)	415
Goodwill, Ending Balance	$ 2,503	$ 2,559