Effects of Derivative Instruments on Financial Statements (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ (18,164)	$ 3,311	$ (24,204)	$ 11,378
Cost of operations
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Income (loss) reclassified from AOCI into income: effective portion	676	93	1,970	(42)
Gain (loss) on foreign currency - net
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Gain (loss) recognized in income: ineffective portion and amount excluded from effectiveness testing	$ 9,115	$ 147	$ 11,465	$ (1,823)