Derivatives (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Derivatives (Textual) [Abstract]
Maximum period in which contracts for the sale of grain to processors or other consumers extend (years)	1 year
Estimated fair value of inventory	$ 6.1	$ 1.0	$ 78.2