Derivatives and Hedging Instruments - Summary of Effects of Derivatives on Cash Flow Hedging Relationships in Company's Statements of Income, Derivatives Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Foreign Currency Exchange Contracts 1 [Member]
Derivative [Line Items]
Gain or (Loss) Recognized in OCI- Effective Portion	$ 989	$ (670)	$ 1,284	$ (593)
Foreign Currency Exchange Contracts 1 [Member] | Salaries and employee benefits [Member]
Derivative [Line Items]
Gain or (Loss) Reclassified from OCI into Income - Effective Portion	151	(153)	683	(468)
Foreign Currency Exchange Contracts 1 [Member] | Other (expense) income [Member]
Derivative [Line Items]
Amount of Gain or (Loss) Recognized - Ineffective Portion and Amount Excluded from Effectiveness Testing	0	0	0	0
Foreign Currency Exchange Contracts 2 [Member]
Derivative [Line Items]
Gain or (Loss) Recognized in OCI- Effective Portion	171	(126)	(19)	24
Foreign Currency Exchange Contracts 2 [Member] | General and administrative expenses [Member]
Derivative [Line Items]
Gain or (Loss) Reclassified from OCI into Income - Effective Portion	26	(28)	95	(75)
Foreign Currency Exchange Contracts 2 [Member] | Other (expense) income [Member]
Derivative [Line Items]
Amount of Gain or (Loss) Recognized - Ineffective Portion and Amount Excluded from Effectiveness Testing	$ 0	$ 0	$ 0	$ 0