Goodwill and Acquired Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 6,716	$ 6,780
Future amortization expense to be recognized in remainder of 2016	19,800
Future amortization expense 2017	27,800
Future amortization expense 2018	23,700
Future amortization expense 2019	21,700
Future amortization expense 2020	$ 17,700