Derivatives and Hedging Instruments - Summary of Fair Value of Derivative Instruments as Recorded in Company's Consolidated Statements of Financial Condition (Detail) - Fair Value, Measurements, Recurring [Member] - Foreign Currency Exchange Contracts [Member] - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Other Liabilities [Member]
Derivative [Line Items]
Foreign currency exchange contracts, liabilities	$ (1,010)	$ (1,037)
Other Assets [Member]
Derivative [Line Items]
Foreign currency exchange contracts, assets	715	768
Fair Value, Inputs, Level 2 [Member] | Other Liabilities [Member]
Derivative [Line Items]
Foreign currency exchange contracts, liabilities	(1,010)	(1,037)
Fair Value, Inputs, Level 2 [Member] | Other Assets [Member]
Derivative [Line Items]
Foreign currency exchange contracts, assets	$ 715	$ 768