Financial Instruments and Risk Management - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended				9 Months Ended
	Sep. 30, 2011 Bushel Project Location	Sep. 30, 2010 Project Bushel	Sep. 30, 2010 Commodity Derivative Contracts Crude Oil bbl	Sep. 30, 2010 Commodity Derivative Contracts Feedstock Inventory bbl	Sep. 30, 2010 Commodity Derivative Contracts Crude Oil and Product Purchases	Sep. 30, 2011 Commodity Derivative Contracts Corn	Sep. 30, 2011 Commodity Derivative Contracts Accounts Receivable	Sep. 30, 2011 Derivative Outstanding Bushel	Sep. 30, 2011 Foreign Exchange Derivative Contracts	Sep. 30, 2010 Foreign Exchange Derivative Contracts	Sep. 30, 2011 Foreign Exchange Derivative Contracts Currency, Malaysian ringgit	Sep. 30, 2010 Foreign Exchange Derivative Contracts Currency, Malaysian ringgit	Sep. 30, 2011 Foreign Exchange Derivative Contracts Currency, U.S. Dollar	Sep. 30, 2010 Foreign Exchange Derivative Contracts Currency, U.S. Dollar
Derivative Instruments and Hedging Activities Disclosure [Line Items]
Notional amount of commodity purchase contracts			900,000	400,000
Increase (decrease) in income before taxes due to the impact of marking to market of derivative contracts					$ 3.8	$ 1.9			$ 4.6	$ 29.7
Asset Derivatives, net							7.3
Fixed-price purchase commitment contracts of bushels of corn	7,900,000	5,400,000
Fixed-price sale of bushels of corn	1,600,000							2,300,000
Short-term derivative instruments											123.3	194.0	38.0	107.0
Notes Payable	$ 350
Notes Payable, maturity date	May 01, 2012
Notes Payable, maturity period	10 years