Financial Instruments and Derivatives - Additional Information (Detail) (USD $)	3 Months Ended			3 Months Ended				3 Months Ended
	Mar. 31, 2013 bu	Dec. 31, 2012	Mar. 31, 2012 bu	Mar. 31, 2013 Commodity derivative contracts	Mar. 31, 2013 Commodity derivative contracts Corn	Mar. 31, 2012 Commodity derivative contracts Corn	Mar. 31, 2013 Interest Rate Swap	Mar. 31, 2013 Foreign exchange derivative contract	Mar. 31, 2012 Foreign exchange derivative contract	Mar. 31, 2013 Foreign exchange derivative contract Currency, Malaysian ringgit	Mar. 31, 2012 Foreign exchange derivative contract Currency, Malaysian ringgit	Mar. 31, 2013 Foreign exchange derivative contract Currency, U.S. Dollar	Mar. 31, 2012 Foreign exchange derivative contract Currency, U.S. Dollar
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Fixed-price purchase commitment contracts of bushels of corn	18,700,000		11,700,000
Outstanding derivative contracts, net volume	6,000,000		11,700,000
Open physical delivery fixed-price purchase commitment contracts	900,000
Outstanding derivative contracts to sell bushels of corn	2,100,000
(Increase) decrease in income before taxes due to the impact of marking to market of derivative contracts					$ 600,000	$ 100,000		$ 2,700,000	$ 6,600,000
Short-term derivative instruments										274,000,000	373,600,000	20,000,000	46,000,000
Maturities of notes payable matured	350,000,000
Deferred loss charged to income	700,000
Loss deferred for fair value of interest rate derivative contracts, net of tax	(17,566,000)	(18,052,000)					17,600,000
Interest expense due to deferred loss on interest rate swaps during the remaining nine months of 2013	$ 2,200,000
Cash deposits related to commodity derivative contracts				11.6