Goodwill and Acquired Intangible Assets - Schedule of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Schedule of Goodwill [Roll Forward]
Balance as of January 1, 2017	$ 1,228,503
Foreign currency translation	1,091
Measurement period adjustments	(90)
Balance as of March 31, 2017	$ 1,229,504