Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Abstract]
Goodwill	$ 19,614	$ 5,520	$ 319
Goodwill, Acquired During Period	14,176	5,231	$ 299
Goodwill, Translation and Purchase Accounting Adjustments	(9)	(30)
Goodwill, Purchase Accounting Adjustments	$ (73)	$ 0