Document And Entity Information - USD ($)	12 Months Ended
	Jan. 31, 2020	Mar. 28, 2020	Jul. 31, 2019
Document Information Line Items
Entity Registrant Name	REX AMERICAN RESOURCES Corp
Document Type	10-K
Current Fiscal Year End Date	--01-31
Entity Common Stock, Shares Outstanding		6,293,322
Entity Public Float			$ 416,091,198
Amendment Flag	false
Entity Central Index Key	0000744187
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Document Period End Date	Jan. 31, 2020
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Interactive Data Current	Yes