Goodwill and Intangible Assets - Summary of Finite Lived Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Cost	$ 94,658	$ 92,908
Accumulated Amortization	44,702	32,180
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	15,867	15,867
Accumulated Amortization	8,609	6,360
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	77,497	77,497
Accumulated Amortization	35,024	26,041
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	1,118	1,118
Accumulated Amortization	698	478
Tradename [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	1,390	1,390
Accumulated Amortization	440	301
Foreign Currency Adjustments [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	(1,214)	(2,964)
Accumulated Amortization	$ (69)	$ (1,000)