| Document and Entity Information - USD ($) | 12 Months Ended | ||
| Sep. 30, 2024 | Dec. 31, 2024 | Mar. 31, 2024 | |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Amendment Flag | false | ||
| Document Annual Report | true | ||
| Document Period End Date | Sep. 30, 2024 | ||
| Current Fiscal Year End Date | --09-30 | ||
| Document Fiscal Year Focus | 2024 | ||
| Document Fiscal Period Focus | FY | ||
| Document Transition Report | false | ||
| 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 | NYSE | ||
| Entity Well-known Seasoned Issuer | No | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Interactive Data Current | Yes | ||
| Entity Filer Category | Non-accelerated Filer | ||
| Entity Small Business | true | ||
| Entity Emerging Growth Company | false | ||
| ICFR Auditor Attestation Flag | false | ||
| Document Financial Statement Error Correction [Flag] | false | ||
| Entity Shell Company | false | ||
| Entity Public Float | $ 8,474,000 | ||
| Entity Common Stock, Shares Outstanding | 10,053,534 | ||
| Auditor Firm ID | 410 | ||
| Auditor Name | Weaver and Tidwell, L.L.P. | ||
| Auditor Location | Little Falls, New Jersey |
