Goodwill and Intangible Assets - Intangibles Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets [Roll Forward]
Balance at January 1	$ 15,120
Amortization expense	(4,047)	$ (4,312)	$ (4,956)
Intangibles assets acquired in asset acquisition	44
Foreign currency translation adjustment	(599)
Balance at December 31	$ 10,518	$ 15,120