Redfield Energy, LLC - Additional Information (Detail) (Redfield, USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2014 Person gal
Redfield
Schedule Of Equity Method Investments [Line Items]
Redfield ethanol production facility	50,000,000
Limited partners capital account units issued	100
Members in board of managers	11
Cost for retrofit of Redfield Facilities	$ 0.4

The number of limited partner units issued.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 5

-Subparagraph (SAB TOPIC 4.F)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section F

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant