Goodwill and Acquired Intangible Assets - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 319,661	$ 275,011
Accumulated Amortization	(160,683)	(142,599)
Net Carrying Amount	158,978	132,412
Completed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	116,891	88,331
Accumulated Amortization	(55,330)	(45,537)
Net Carrying Amount	61,561	42,794
Customer-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	191,710	173,600
Accumulated Amortization	(99,933)	(91,160)
Net Carrying Amount	91,777	82,440
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,870	8,890
Accumulated Amortization	(3,328)	(4,224)
Net Carrying Amount	3,542	4,666
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,700	3,700
Accumulated Amortization	(1,602)	(1,188)
Net Carrying Amount	2,098	2,512
Acquired license rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	490	490
Accumulated Amortization	(490)	(490)
Net Carrying Amount	$ 0	$ 0