Intangible Assets - Schedule of Intangible Assets, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Acquisition intangible assets, net, Gross Carrying Amount	$ 75,775	$ 75,775
Acquisition intangible assets, net, Accumulated Amortization	(65,418)	(62,181)
Acquisition intangible assets, net, Net Carrying Amount	10,357	13,594
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Acquisition intangible assets, net, Gross Carrying Amount	47,696	47,696
Acquisition intangible assets, net, Accumulated Amortization	(41,981)	(40,696)
Acquisition intangible assets, net, Net Carrying Amount	5,715	7,000
Trade Name
Finite Lived Intangible Assets [Line Items]
Acquisition intangible assets, net, Gross Carrying Amount	6,072	6,072
Acquisition intangible assets, net, Accumulated Amortization	(5,680)	(5,192)
Acquisition intangible assets, net, Net Carrying Amount	392	880
Technology
Finite Lived Intangible Assets [Line Items]
Acquisition intangible assets, net, Gross Carrying Amount	22,007	22,007
Acquisition intangible assets, net, Accumulated Amortization	(17,757)	(16,293)
Acquisition intangible assets, net, Net Carrying Amount	$ 4,250	$ 5,714