Derivative Instruments and Hedging Activities - Additional Information (Detail) (Commodity Contract, Cost of Sales, USD $)	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Commodity Contract \| Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Recognized gain (loss) in cost of sales on commodity contracts not designated as hedging instruments	$ (1,342,000)	$ 1,071,000	$ (681,000)	$ 1,367,000

- Definition

The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments not designated as hedging instruments.

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