Derivatives (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
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	$ 0.3	$ 7.7	$ 6.1