Business Combinations, Goodwill and Intangible Assets - Summary of Company's Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 99,711	$ 99,487
Accumulated amortization	(50,255)	(46,617)
Total	49,456	52,870
Intangible assets, gross	100,611	100,387
Intangible assets, net	50,356	53,770
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	75,249	75,181
Accumulated amortization	(35,647)	(32,968)
Total	39,602	42,213
Leasehold benefits
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	2,845	2,715
Accumulated amortization	(2,405)	(2,247)
Total	440	468
Developed technology
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	14,209	14,186
Accumulated amortization	(7,034)	(6,468)
Total	7,175	7,718
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	2,045	2,045
Accumulated amortization	(1,653)	(1,612)
Total	392	433
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	5,363	5,360
Accumulated amortization	(3,516)	(3,322)
Total	1,847	2,038
Trade names and trademarks
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets, trade names and trademarks	$ 900	$ 900