No definition available.

Name:	rex_CommodityFuturesQuantity
Namespace Prefix:	rex_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

Name:	rex_DERIVATIVEFINANCIALINSTRUMENTSDetailsLineItems
Namespace Prefix:	rex_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	rex_ForwardPurchaseContractsQuantity
Namespace Prefix:	rex_
Data Type:	num:volumeItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of assets pledged to secure a debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentCollateralAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of increase in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

+ Details

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

- Definition

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

+ Details

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

- Details

Name:	us-gaap_TradingActivityByTypeAxis=rex_CornMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ContractWithCustomerDurationAxis=rex_ShortSellMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_TradingActivityByTypeAxis=rex_EthanolMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

DERIVATIVE FINANCIAL INSTRUMENTS (Details) l in Millions, bu in Millions	3 Months Ended
	Apr. 30, 2019 USD ($) bu l	Apr. 30, 2018 USD ($)	Jan. 31, 2019 bu
DERIVATIVE FINANCIAL INSTRUMENTS (Details) [Line Items]
Debt Instrument, Collateral Amount	$ 82,000
Gain (Loss) on Derivative Instruments, Net, Pretax	369,000	$ (565,000)
Derivative, Gain on Derivative	$ 302,000	$ 44,000
Corn [Member]
DERIVATIVE FINANCIAL INSTRUMENTS (Details) [Line Items]
Forward Purchase Contracts, Quantity (in US Bushels) \| bu	1.9		1.3
Corn [Member] \| Short/Sell [Member]
DERIVATIVE FINANCIAL INSTRUMENTS (Details) [Line Items]
Commodity Futures, Quantity \| bu	0.6		2.0
Ethanol [Member]
DERIVATIVE FINANCIAL INSTRUMENTS (Details) [Line Items]
Commodity Futures, Quantity \| l	4.0