Goodwill and Acquired Intangible Assets - Schedule of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Schedule of Goodwill [Roll Forward]
Balance as of January 1, 2020	$ 1,600,265
Measurement period adjustments related to acquisitions completed in prior years	(1,056)
Foreign currency translation	(290)
Balance as of September 30, 2020	$ 1,598,919