| Document and Entity Information | Dec. 16, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 16, 2024 |
| Entity File Number | 1-5103 |
| Entity Registrant Name | BARNWELL INDUSTRIES, INC. |
| Entity Central Index Key | 0000010048 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 72-0496921 |
| Entity Address, Address Line One | 1100 Alakea Street |
| Entity Address, Address Line Two | Suite 500 |
| Entity Address, City or Town | Honolulu |
| Entity Address, State or Province | HI |
| Entity Address, Postal Zip Code | 96813 |
| City Area Code | 808 |
| Local Phone Number | 531-8400 |
| Title of 12(b) Security | Common Stock, $0.50 Par Value |
| Trading Symbol | BRN |
| Security Exchange Name | NYSEAMER |
| Entity Emerging Growth Company | false |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
