Goodwill and Acquired Intangible Assets - Schedule of Acquired Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 279,611	$ 192,571
Accumulated Amortization	(130,393)	(115,142)
Net Carrying Amount	149,218	77,429
Completed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	92,431	65,631
Accumulated Amortization	(42,299)	(35,476)
Net Carrying Amount	50,132	30,155
Customer-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	173,600	115,100
Accumulated Amortization	(82,859)	(75,563)
Net Carrying Amount	90,741	39,537
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,890	7,950
Accumulated Amortization	(3,385)	(2,623)
Net Carrying Amount	5,505	5,327
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,200	3,400
Accumulated Amortization	(1,360)	(990)
Net Carrying Amount	2,840	2,410
Acquired license rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	490	490
Accumulated Amortization	(490)	(490)
Net Carrying Amount	$ 0	$ 0