Net (Gains) Losses Reclassified from Accumulated Other Comprehensive Loss (Detail) - Derivatives designated as cash flow hedging instruments - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income (loss), Effective portion, Net, Total	$ (2)	$ 75	$ 180	$ 218
Gain (loss) reclassified from accumulated OCI into income, Effective portion, Net, Total	2	(69)	(186)	(191)
Foreign exchange option contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income (loss), Effective portion, Net, Total	1	44	88	118
Gain (loss) reclassified from accumulated OCI into income, Effective portion, Net, Total	(1)	(21)	(88)	(70)
Foreign exchange forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in other comprehensive income (loss), Effective portion, Net, Total	(3)	31	92	100
Gain (loss) reclassified from accumulated OCI into income, Effective portion, Net, Total	$ 3	$ (48)	$ (98)	$ (121)