Financial Instruments - Derivative Instruments Measured at Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Liabilities		$ 13,555
Foreign currency contracts
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Assets	$ 10,333	5,137
Total Fair Value, Derivative Liabilities	4,771	12,186
Interest rate swaps
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Liabilities		1,369
Fair Value of Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Liabilities		9,211
Fair Value of Derivatives Designated as Hedging Instruments [Member] | Foreign currency contracts
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Assets	2,644	1,159
Total Fair Value, Derivative Liabilities	371	7,842
Fair Value of Derivatives Designated as Hedging Instruments [Member] | Interest rate swaps
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Liabilities		1,369
Fair Value of Derivatives Not Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Liabilities		4,344
Fair Value of Derivatives Not Designated as Hedging Instruments [Member] | Foreign currency contracts
Derivatives, Fair Value [Line Items]
Total Fair Value, Derivative Assets	7,689	3,978
Total Fair Value, Derivative Liabilities	$ 4,400	$ 4,344