Goodwill and Intangible Assets, Net, Carrying Amount of Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Goodwill
Balance at the beginning of the period			$ 124,479
Acquisitions			10,066
Foreign exchange			2,615
Balance at the end of the period	$ 137,160	$ 124,993	137,160	$ 124,993
Intangible Assets
Balance at the beginning of the period			22,864
Acquisitions			10,301
Amortization	(1,700)	(1,500)	(3,195)	(3,000)
Foreign exchange			834
Balance at the end of the period	$ 30,804	$ 24,912	$ 30,804	$ 24,912