Goodwill and Acquired Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 38,581	$ 33,311	$ 30,904
Future amortization expense, year 1	41,000
Future amortization expense, year 2	36,200
Future amortization expense, year 3	31,000
Future amortization expense, year 4	23,900
Future amortization expense, year 5	$ 16,600