Derivative Financial Instruments - Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Detail) (Derivative designated as hedging instrument [Member], USD $)	Sep. 30, 2012	Dec. 31, 2011
Zero Cost Collars [Member]
Asset Derivatives:
Other current assets	$ 74
Liability Derivatives:
Derivative Liability Fair Value		2,956
Forward [Member]
Liability Derivatives:
Derivative Liability Fair Value	$ 1,818	$ 6,801