Mark-to-Market Impact on Earnings Resulting from Hedging Activities (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Average rate currency options and forward contracts | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments gain (loss) recognized in income	$ (262)	$ (195)	$ (60)
Interest Rate Swap | Interest income (expense)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments gain (loss) recognized in income	54	(24)	(12)
Cashless collar contracts | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments gain (loss) recognized in income			$ 547