Financial Instruments - Derivative Instruments Which Were Not Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Not Designated as Hedging Instrument [Member] | Foreign currency contracts [Member] | Other income (expense), net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) Gain Recognized in Income on Derivative	$ 4,024	$ (3,313)	$ (9,157)	$ (6,860)