Intangible Assets - Schedule of Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Gross	$ 47,185	$ 41,056
Accumulated Amortization	(26,388)	(21,982)
Net	20,797	19,074
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross	15,416	15,270
Accumulated Amortization	(8,741)	(7,347)
Net	$ 6,675	$ 7,923
Customer Relationships | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	3 years	3 years
Customer Relationships | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	10 years	10 years
Developed Technology
Finite Lived Intangible Assets [Line Items]
Gross	$ 30,780	$ 24,781
Accumulated Amortization	(16,692)	(13,785)
Net	$ 14,088	$ 10,996
Developed Technology | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	3 years	3 years
Developed Technology | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	8 years	8 years
Noncompete Agreements
Finite Lived Intangible Assets [Line Items]
Gross	$ 569	$ 586
Accumulated Amortization	(535)	(446)
Net	$ 34	$ 140
Noncompete Agreements | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	3 years	3 years
Noncompete Agreements | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	5 years	5 years
Tradename and Trademarks
Finite Lived Intangible Assets [Line Items]
Gross	$ 420	$ 419
Accumulated Amortization	$ (420)	(404)
Net		$ 15
Tradename and Trademarks | Minimum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	1 year	1 year
Tradename and Trademarks | Maximum
Finite Lived Intangible Assets [Line Items]
Average Useful Life (Years)	4 years	4 years