Goodwill and Acquired Intangible Assets - Schedule of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 426,121	$ 399,191
Accumulated Amortization	(250,090)	(230,843)
Net Carrying Amount	176,031	168,348
Completed technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	154,091	145,091
Accumulated Amortization	(91,103)	(81,587)
Net Carrying Amount	62,988	63,504
Customer-related intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	263,410	245,710
Accumulated Amortization	(153,970)	(144,786)
Net Carrying Amount	109,440	100,924
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	730	700
Accumulated Amortization	(413)	(306)
Net Carrying Amount	317	394
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,400	7,200
Accumulated Amortization	(4,114)	(3,674)
Net Carrying Amount	3,286	3,526
Acquired license rights
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	490	490
Accumulated Amortization	(490)	(490)
Net Carrying Amount	$ 0	$ 0