Discontinued Operations (Details) - Schedule Of Discontinued Items Statement of Operations - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 31, 2022	Jul. 31, 2021	Jul. 31, 2022	Jul. 31, 2021
Schedule Of Discontinued Items Statement Of Operations Abstract
Net sales and revenue	[1]		$ 165		$ 227
Cost of Sales			3,245		4,982
Gross loss			(3,080)		(4,755)
Selling, general and administrative			(351)		(436)
Loss before income taxes			(3,431)		(5,191)
Benefit for income taxes			5,444		7,639
Net income from discontinued operations, net of tax			2,013		2,448
Net loss attributable to noncontrolling interests			153		233
Net income (loss) attributable to REX common shareholders			$ 2,166		$ 2,681

[1] Refined coal sales were recorded net of the cost of coal as the Company purchased the coal feedstock from the customer to which the processed refined coal was sold.