Change in Fair Value of Forward Contracts (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) from the change in the fair value of forward contracts included in other income (expense), net	$ 565	$ (1,421)	$ 286	$ (3,718)
Foreign currency transaction (loss) gain from the remeasurement of foreign currency assets and liabilities	(917)	306	(241)	1,682
Net gain (loss)	$ (352)	$ (1,115)	$ 45	$ (2,036)