Financial Instruments and Risk Management - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012 bu	Dec. 31, 2011 bu		Dec. 31, 2010
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Fixed-price purchase commitment contracts of bushels of corn	19,200,000	8,000,000
Open physical delivery fixed-price purchase commitment contracts	1,000,000	1,100,000
Outstanding derivative contracts to sell bushels of corn		2,900,000
Outstanding derivative contracts, net volume	6,300,000	6,700,000
Fair values of foreign currency derivative contracts	$ 1,031,000	$ 8,459,000
Maturities of notes payable matured	350,000,000	340,041,000	[1]	332,038,000	[1]
Deferred loss charged to income	1,852,000
Loss deferred for fair value of interest rate derivative contracts, net of tax	(18,052,000)	(16,852,000)
Interest expense due to deferred loss on interest rate swaps during 2013	2,960,000
Canada
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Foreign currency short-term derivative instruments	154,000,000	16,000,000
Malaysia
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Foreign currency short-term derivative instruments		472,000,000
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Loss deferred for fair value of interest rate derivative contracts, net of tax	27,778,000
Nondesignated | Commodity derivative contracts | Other Liabilities
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Liability Derivatives		292,000
Nondesignated | Commodity derivative contracts | Other Assets
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Asset Derivatives	$ 2,941,000

[1] Reclassified to conform to current presentation.