Related-Party Transactions (Details) (One Earth Energy [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2014	Jul. 31, 2013
One Earth Energy [Member]
Related-Party Transactions (Details) [Line Items]
Costs and Expenses, Related Party	$ 40.4	$ 78.7	$ 85.2	$ 150.4

Costs of sales and operating expenses for the period incurred from transactions with related parties.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.2)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Name:	us-gaap_CostsAndExpensesRelatedParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration