Income Per Share from Continuing Operations Attributable to REX Common Shareholders (Details) - Schedule of Earnings Per Share, Basic and Diluted (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Apr. 30, 2015	Apr. 30, 2014
Schedule of Earnings Per Share, Basic and Diluted [Abstract]
Basic income per share from continuing operations attributable to REX common shareholders (in Dollars)	$ 3,927	$ 21,739
Basic income per share from continuing operations attributable to REX common shareholders	7,900	8,117
Basic income per share from continuing operations attributable to REX common shareholders (in Dollars per share)	$ 0.50	$ 2.68
Effect of stock options		32
Diluted income per share from continuing operations attributable to REX common shareholders (in Dollars)	$ 3,927	$ 21,739
Diluted income per share from continuing operations attributable to REX common shareholders	7,900	8,149
Diluted income per share from continuing operations attributable to REX common shareholders (in Dollars per share)	$ 0.50	$ 2.67

Income Per Share from Continuing Operations Attributable to REX Common Shareholders (Details) - Schedule of Earnings Per Share, Basic and Diluted (USD $)
In Thousands, except Per Share data, unless otherwise specified

3 Months Ended

Apr. 30, 2015

Apr. 30, 2014

Schedule of Earnings Per Share, Basic and Diluted [Abstract]

Basic income per share from continuing operations attributable to REX common shareholders (in Dollars)

$ 3,927rex_IncomeLossFromContinuingOperationsBasic

$ 21,739rex_IncomeLossFromContinuingOperationsBasic

Basic income per share from continuing operations attributable to REX common shareholders

7,900us-gaap_WeightedAverageNumberOfSharesOutstandingBasic

8,117us-gaap_WeightedAverageNumberOfSharesOutstandingBasic

Basic income per share from continuing operations attributable to REX common shareholders (in Dollars per share)

$ 0.50us-gaap_IncomeLossFromContinuingOperationsPerBasicShare

$ 2.68us-gaap_IncomeLossFromContinuingOperationsPerBasicShare

Effect of stock options

32us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment

Diluted income per share from continuing operations attributable to REX common shareholders (in Dollars)

$ 3,927rex_IncomeLossFromContinuingOperationsDiluted

$ 21,739rex_IncomeLossFromContinuingOperationsDiluted

Diluted income per share from continuing operations attributable to REX common shareholders

7,900us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding

8,149us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding

Diluted income per share from continuing operations attributable to REX common shareholders (in Dollars per share)

$ 0.50us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare

$ 2.67us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare

- Definition

Amount of income (loss) from continuing operations attributable to the parent basic. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

+ References

No definition available.

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- Definition

Amount of income (loss) from continuing operations attributable to the parent diluted. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

+ References

No definition available.

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- Definition

The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 45

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- Definition

The amount of net income (loss) derived from continuing operations during the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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

-Publisher FASB

-Name Accounting Standards Codification

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

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-Subparagraph (SX 210.5-03.21)

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

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- Definition

The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

+ References

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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

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- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

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