Goodwill and Acquired Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 7,569	$ 6,716
Future amortization expense to be recognized in remainder of 2017	21,600
Future amortization expense 2018	26,400
Future amortization expense 2019	25,000
Future amortization expense 2020	21,100
Future amortization expense 2021	$ 16,600