SEGMENT REPORTING (Details) - Schedule Of Segment Results And Assets - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Jan. 31, 2021	Oct. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Net sales and revenue:
Net sales and revenue:		$ 126,018	$ 124,251	$ 39,327	$ 83,250	$ 120,920	$ 86,671	$ 105,868	$ 104,575	$ 372,846	$ 418,034	$ 486,671
Segment gross profit (loss):
Segment gross profit (loss):		$ 6,843	$ 17,679	$ (1,331)	$ (9,330)	$ 6,593	$ (1,758)	$ 4,004	$ 3,646	13,861	12,485	30,215
(Loss) income before income taxes:
Income (loss) before income taxes:										(1,482)	(1,169)	14,588
Benefit (provision) for income taxes:
Benefit (provision) for income taxes:										7,100	12,813	22,922
Net income attributable to REX common shareholders:
Segment profit (loss):										3,001	7,427	31,645
Sales of products, ethanol and by-products segment:
Sales of products, ethanol and by-products segment:										372,664	417,700	485,885
Interest income:
Interest income:										964	4,120	3,514
Depreciation expense:
Depreciation expense:										20,906	23,007	24,828
Equity in income of unconsolidated affiliates:
Equity in income of unconsolidated affiliates:										500	1,392	1,536
Ethanol [Member]
Net sales and revenue:
Net sales and revenue:										372,664	417,700	485,885
Segment gross profit (loss):
Segment gross profit (loss):										19,533	20,402	43,856
(Loss) income before income taxes:
Income (loss) before income taxes:										6,696	8,469	31,545
Benefit (provision) for income taxes:
Benefit (provision) for income taxes:										(31)	1,528	(2,343)
Net income attributable to REX common shareholders:
Segment profit (loss):										3,788	5,439	23,346
Sales of products, ethanol and by-products segment:
Sales of products, ethanol and by-products segment:										284,191	321,434	368,319
Interest income:
Interest income:										675	2,949	2,460
Depreciation expense:
Depreciation expense:										18,081	20,182	22,004
Equity in income of unconsolidated affiliates:
Equity in income of unconsolidated affiliates:										500	1,392	1,536
Refined Coal [Member]
Net sales and revenue:
Net sales and revenue:	[1]									182	334	786
Segment gross profit (loss):
Segment gross profit (loss):										(5,672)	(7,917)	(13,641)
(Loss) income before income taxes:
Income (loss) before income taxes:										(5,826)	(7,778)	(15,204)
Benefit (provision) for income taxes:
Benefit (provision) for income taxes:										6,554	10,828	24,674
Net income attributable to REX common shareholders:
Segment profit (loss):										988	3,391	10,148
Sales of products, refined coal segment:
Sales of products, refined coal segment:										182	334	786
Depreciation expense:
Depreciation expense:										2,790	2,790	2,784
Corporate and Other [Member]
(Loss) income before income taxes:
Income (loss) before income taxes:										(2,352)	(1,860)	(1,753)
Benefit (provision) for income taxes:
Benefit (provision) for income taxes:										577	457	591
Net income attributable to REX common shareholders:
Segment profit (loss):										(1,775)	(1,403)	(1,849)
Interest income:
Interest income:										289	1,171	1,054
Depreciation expense:
Depreciation expense:										35	35	40
Dried Distillers Grains [Member]
Sales of products, ethanol and by-products segment:
Sales of products, ethanol and by-products segment:										71,774	71,755	85,417
Non-Food Grade Corn Oil [Member]
Sales of products, ethanol and by-products segment:
Sales of products, ethanol and by-products segment:										15,066	17,135	20,097
Modified Distillers Grains [Member]
Sales of products, ethanol and by-products segment:
Sales of products, ethanol and by-products segment:										2,626	7,240	11,950
Derivative Financial Instrument Losses [Member]
Sales of products, ethanol and by-products segment:
Sales of products, ethanol and by-products segment:										(1,167)
Other Segments [Member]
Sales of products, ethanol and by-products segment:
Sales of products, ethanol and by-products segment:										$ 174	$ 136	$ 102

[1] Sales in the refined coal segment are recorded net of the cost of coal as the Company purchases the coal feedstock from the customer to which refined coal is sold.