Derivatives and Fair Value of Financial Instruments (Details 3) (USD $)	Mar. 31, 2012 agreement	Dec. 31, 2011 agreement	Aug. 28, 2010 Y	May 29, 2010 Y agreement
Net commodity purchase contracts | Soybean oil
Derivative commodity instruments
Nonmonetary notional amount		2,580,000
Net commodity purchase contracts | Soybean meal
Derivative commodity instruments
Nonmonetary notional amount		23,300
Net commodity purchase contracts | Hogs
Derivative commodity instruments
Nonmonetary notional amount	7,160,000	2,280,000
Net commodity purchase contracts | Sugar
Derivative commodity instruments
Nonmonetary notional amount	1,213,000
Net commodity sale contracts | Grain
Derivative commodity instruments
Nonmonetary notional amount	595,000	10,599,000
Net commodity sale contracts | Soybean meal
Derivative commodity instruments
Nonmonetary notional amount	114,000
Net commodity sale contracts | Heating oil
Derivative commodity instruments
Nonmonetary notional amount	714,000	1,176,000
Foreign currency exchange agreements
Derivative commodity instruments
Aggregate notional amount	$ 127,029,000	$ 158,266,000
Interest rate exchange agreements
Derivative commodity instruments
Aggregate notional amount	100,000,000	100,000,000
Notional amounts			$ 25,000,000	$ 25,000,000
Number of derivative agreements entered	4	4		3
Term of derivative contract (in years)			10	10