Related-Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
One Earth Energy And Nu Gen Energy [Member]
Related-Party Transactions (Details) [Line Items]
Costs and Expenses, Related Party	$ 36.0	$ 38.0	$ 80.4	$ 76.3

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=63488584&loc=d3e20235-122688

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