Financial Instruments - Derivative Instruments Notional Amount Outstanding (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Forward Currency Contracts [Member]
Schedule Of Information By Major Category Of Credit Derivatives Contracts [Line Items]
Derivative instruments outstanding	$ 143,483	$ 147,078
Interest Rate Swaps [Member]
Schedule Of Information By Major Category Of Credit Derivatives Contracts [Line Items]
Derivative instruments outstanding	$ 100,000	$ 100,000