Business Combinations, Goodwill and Intangible Assets - Summary of Company's Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 99,487	$ 86,654
Accumulated Amortization	(46,617)	(34,821)
Finite-lived intangible assets, net	52,870	51,833
Intangible assets, gross	100,387	87,554
Intangible assets, net	53,770	52,733
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	75,181	64,816
Accumulated Amortization	(32,968)	(24,215)
Finite-lived intangible assets, net	42,213	40,601
Leasehold benefits
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	2,715	2,789
Accumulated Amortization	(2,247)	(2,109)
Finite-lived intangible assets, net	468	680
Developed technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	14,186	12,234
Accumulated Amortization	(6,468)	(4,363)
Finite-lived intangible assets, net	7,718	7,871
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	2,045	2,045
Accumulated Amortization	(1,612)	(1,451)
Finite-lived intangible assets, net	433	594
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	5,360	4,770
Accumulated Amortization	(3,322)	(2,683)
Finite-lived intangible assets, net	2,038	2,087
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, trade names and trademarks	$ 900	$ 900