Goodwill and Intangible Assets - Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($)
Goodwill [Roll Forward]
Goodwill balance at beginning of period	$ 335,433
Effect of foreign exchange	(1,069)
Additions and adjustments as the result of acquisitions	17,794
Goodwill balance at end of period	$ 352,158