Business Combinations, Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands					3 Months Ended								12 Months Ended
	Oct. 22, 2016	Sep. 01, 2016	Jul. 01, 2016	Jun. 19, 2015	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Vesting period (in years)				4 years
Acquisition related costs					$ 633								$ 633
Revenue of acquirees since acquisition													6,855
Amortization expense					$ 3,592	$ 2,848	$ 2,718	$ 2,715	$ 2,717	$ 2,642	$ 2,808	$ 2,059	$ 11,873	$ 10,226	$ 6,623
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Remaining amortization period (in years)													5 years 9 months 18 days
Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Remaining amortization period (in years)													4 years 10 months 24 days
Non-compete agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Remaining amortization period (in years)													2 years 6 months
Leasehold benefits
Acquired Finite-Lived Intangible Assets [Line Items]
Remaining amortization period (in years)													2 years 4 months 24 days
Trade names and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Remaining amortization period (in years)													5 years 3 months 18 days
Liss Systems Limited
Acquired Finite-Lived Intangible Assets [Line Items]
Cash consideration transferred			$ 5,111
Liss Systems Limited | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life (in years)													5 years
Liss Systems Limited | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life (in years)													10 years
Liss Systems Limited | Trade names and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life (in years)													3 years
IQR Consulting Inc.
Acquired Finite-Lived Intangible Assets [Line Items]
Cash consideration transferred		$ 5,092
IQR Consulting Inc. | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life (in years)		8 years
Datasource Consulting, LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Cash consideration transferred	$ 20,318
Datasource Consulting, LLC | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	6 years
Datasource Consulting, LLC | Developed technology
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	5 years
Datasource Consulting, LLC | Trade names and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	3 years
Restricted Stock | Liss Systems Limited
Acquired Finite-Lived Intangible Assets [Line Items]
Restricted common stock issued (in shares)			33,459
Fair value of restricted common stock issued			$ 1,754
Vesting period (in years)			4 years
Restricted Stock | IQR Consulting Inc.
Acquired Finite-Lived Intangible Assets [Line Items]
Restricted common stock issued (in shares)		21,987
Fair value of restricted common stock issued		$ 1,125
Vesting period (in years)		4 years
Restricted Stock | Datasource Consulting, LLC
Acquired Finite-Lived Intangible Assets [Line Items]
Restricted common stock issued (in shares)	93,604
Fair value of restricted common stock issued	$ 4,483
Vesting period (in years)	4 years