Goodwill and Acquired Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of acquired intangible assets	$ 6,752	$ 8,403	$ 13,532	$ 15,251
Future amortization expense to be recognized in remainder of 2015	13,500		13,500
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