Selected Quarterly Data (Unaudited) (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Jun. 30, 2012	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Selected Quarterly Data (Unaudited) (Textual) [Abstract]
Gain on sale of oilseed processing business	$ 0	$ 0	$ 31,278,000	$ 31,278	$ 31,278	$ 31,278	$ 0	$ 0

Gain (loss) from sale or disposal of an organization or integrated set of activities (for example, but not limited to, a partnership or corporation) engaged in providing a product or service in a commercial, industrial, or professional environment.

No definition available.

Name:	us-gaap_GainLossOnSaleOfBusiness
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration