Document And Entity Information - USD ($)	12 Months Ended
	Jan. 31, 2018	Mar. 28, 2018	Jul. 31, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	REX AMERICAN RESOURCES Corp
Document Type	10-K
Current Fiscal Year End Date	--01-31
Entity Common Stock, Shares Outstanding		6,496,518
Entity Public Float			$ 576,633,450
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, 2018
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY