Financial Instruments - Derivative Instruments Which Were Not Designated as Hedging Instruments (Detail) - Not Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Foreign currency contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) Gain Recognized in Income on Derivative	$ (9,273)	$ (3,054)	$ (12,888)	$ (13,181)
Non-Deal Contingent Swaps | Foreign currency contracts | Other income (expense), net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) Gain Recognized in Income on Derivative	4,685	(3,054)	1,070	(13,181)
Deal Contingent Swaps | Foreign currency contracts | Other income (expense), net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) Gain Recognized in Income on Derivative	10,979	0	10,979	0
Deal Contingent Swaps | Interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss) Gain Recognized in Income on Derivative	$ (24,937)	$ 0	$ (24,937)	$ 0