Derivative Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative [Line Items]
Other Comprehensive Income (Loss), Net of Tax - Currency Translation Adjustment	$ (30,674,000)	$ 35,089,000	$ (26,248,000)	$ 46,593,000
Net Investment Hedges | Foreign Currency Contracts
Derivative [Line Items]
Other Comprehensive Income (Loss), Net of Tax - Currency Translation Adjustment	$ 0		$ (1,400,000)