Financial Instruments and Fair Value Measurements - Summary of Recognized Unrealized Gains (Losses) in Foreign Currency and Derivative Gains (Losses) Net on Remeasurement of Unhedged Portion of Debt and Accrued Interest (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivatives Fair Value [Line Items]
Foreign currency translation gains, net	$ 60,080	$ 4,770
Forward Contracts [Member]
Derivatives Fair Value [Line Items]
Foreign currency translation gains, net		$ (24,000)