Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage (USD $) In Thousands, unless otherwise specified	3 Months Ended
Apr. 30, 2014	Apr. 30, 2013
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Net sales and revenues	$ 155,936	$ 178,424
Gross profit	36,550	8,992
Income from continuing operations before income taxes and noncontrolling interests	38,032	5,837
Alternative Energy Segment [Member] \| Ethanol [Member]
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Sale of Product	76.00%	74.00%
Alternative Energy Segment [Member] \| Dried Distillers Grains [Member]
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Sale of Product	20.00%	17.00%
Alternative Energy Segment [Member] \| Modified Distillers Grains [Member]
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Sale of Product	1.00%	6.00%
Alternative Energy Segment [Member] \| Other Products [Member]
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Sale of Product	3.00%	3.00%
Alternative Energy Segment [Member]
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Net sales and revenues	155,827	178,324
Gross profit	36,614	9,026
Additions to property and equipment	38,876	6,626
Sale of Product	100.00%	100.00%
Real Estate Segment [Member]
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Net sales and revenues	109	100
Gross profit	(64)	(34)
Additions to property and equipment	(91)	(97)
Lease revenue	100.00%	100.00%
Corporate Segment [Member]
Segment Reporting (Details) - Schedule of Segment Reporting Information, Profit Loss And Revenue Percentage [Line Items]
Additions to property and equipment	$ (753)	$ (692)

The percentage of net lease revenue to total net revenue from the lease as of year end.

No definition available.

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- Definition

The percentage of net product revenue to total net revenue from the sale of goods as of year end.

+ References

No definition available.

+ Details

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Namespace Prefix:	rex_
Data Type:	num:percentItemType
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- Details

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- Definition

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

+ References

+ Details

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

- Definition

This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 5

+ Details

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- Definition

Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

+ References

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 210.5-03.1)

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

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