Financial Instruments - Derivative Instruments Which Were Not Designated as Hedging Instruments (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Foreign currency contracts
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 34,741	$ 4,024	$ 21,853	$ (9,157)
Non-Deal Contingent Swaps | Foreign currency contracts | Other income (expense), net
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	8,277	4,024	9,347	(9,157)
Deal Contingent Swaps | Foreign currency contracts | Other income (expense), net
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1,175	0	12,154	0
Deal Contingent Swaps | Interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 25,289	$ 0	$ 352	$ 0