Derivatives and Hedging - Currency Exposures in Notional Amounts (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivatives and their notional amounts	$ 250,700	$ 239,400
Accounts Receivable
Derivatives, Fair Value [Line Items]
Derivatives and their notional amounts	50,010	44,427
Other assets and liabilities, net
Derivatives, Fair Value [Line Items]
Derivatives and their notional amounts	39,367	46,550
Intercompany balances
Derivatives, Fair Value [Line Items]
Derivatives and their notional amounts	161,351	144,477
Assets
Derivatives, Fair Value [Line Items]
Derivatives and their notional amounts	$ 250,728	$ 235,454