| Document and Entity Information | Dec. 20, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Central Index Key | 0001438731 |
| Document Period End Date | Dec. 20, 2021 |
| Entity Registrant Name | ALJ Regional Holdings, Inc. |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-37689 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 13-4082185 |
| Entity Address, Address Line One | 244 Madison Avenue, PMB #358 |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10016 |
| City Area Code | (888) |
| Local Phone Number | 486-7775 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.01 per share |
| Trading Symbol | ALJJ |
| Security Exchange Name | NASDAQ |
