Investment Assets (Excluding Equity and Cost Method Investments) and Derivatives Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Derivative Financial Instruments, Liabilities | Interest rate derivatives
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of liabilities, recurring basis	$ (377)	$ (4,024)
Derivative Financial Instruments, Liabilities | Foreign currency contracts
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of liabilities, recurring basis	(166)	(8,802)
Derivative Financial Instruments, Assets | Interest rate derivatives
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	21,077	10,156
Derivative Financial Instruments, Assets | Foreign currency contracts
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	4,598	405
Certificates of deposit (non-U.S.)
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	46,698	12,809
Corporate bonds
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis		11,065
Corporate obligations
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	14	13
Money markets
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	37	38
Mutual funds
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	82	79
Other Investments
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	5,529	5,588
Level 1 | Money markets
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	37	38
Level 1 | Mutual funds
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	82	79
Level 2 | Derivative Financial Instruments, Liabilities | Interest rate derivatives
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of liabilities, recurring basis	(377)	(4,024)
Level 2 | Derivative Financial Instruments, Liabilities | Foreign currency contracts
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of liabilities, recurring basis	(166)	(8,802)
Level 2 | Derivative Financial Instruments, Assets | Interest rate derivatives
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	21,077	10,156
Level 2 | Derivative Financial Instruments, Assets | Foreign currency contracts
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	4,598	405
Level 2 | Certificates of deposit (non-U.S.)
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	46,698	12,809
Level 2 | Corporate bonds
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis		11,065
Level 2 | Corporate obligations
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	14	13
Level 2 | Other Investments
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]
Fair value of assets, recurring basis	$ 5,529	$ 5,588