| Document And Entity Information | Aug. 26, 2020 |
| Document Information Line Items | |
| Entity Registrant Name | REX AMERICAN RESOURCES CORPORATION |
| Trading Symbol | REX |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Central Index Key | 0000744187 |
| Document Period End Date | Aug. 26, 2020 |
| Entity Emerging Growth Company | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-09097 |
| Entity Tax Identification Number | 31-1095548 |
| Entity Address, Address Line One | 7720 Paragon Road |
| Entity Address, City or Town | Dayton |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 45459 |
| City Area Code | 937 |
| Local Phone Number | 276-3931 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Commons stock, $0.01 par value |
| Security Exchange Name | NYSE |
