Fair Value Measurements - Gains and Losses on Derivative Instruments in Consolidated Statement of Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss)/Gain Recognized in Other Comprehensive Income on Derivatives	$ (1,121)
Amount of (Loss)/Gain Recognized in Other Comprehensive Income on Derivatives		$ 2,139
Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss)/Gain Recognized in Other Comprehensive Income on Derivatives	(1,183)
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income	(62)
Not designated as hedging instruments: | Foreign Currency Derivative | Other non-operating expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Loss Recognized in Income on Derivatives for the	$ (1,006)	(2,281)
Derivatives Designated as Cash Flow Hedges | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Loss)/Gain Recognized in Other Comprehensive Income on Derivatives		646
Amount of Loss Reclassified from Accumulated Other Comprehensive Loss into Income		$ (1,493)