Goodwill and Acquired Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 6,752	$ 8,403	$ 20,284	$ 23,654
Future amortization expense to be recognized in remainder of 2015	6,800		6,800
Future amortization expense 2016	26,400		26,400
Future amortization expense 2017	27,600		27,600
Future amortization expense 2018	23,300		23,300
Future amortization expense 2019	$ 21,000		$ 21,000