| Cover | Aug. 04, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Nov. 8, 2021 |
| Entity Registrant Name | DLH Holdings Corp. |
| Entity Incorporation, State or Country Code | NJ |
| Entity File Number | 0-18492 |
| Entity Tax Identification Number | 22-1899798 |
| Entity Address, Address Line One | 3565 Piedmont Road, NE |
| Entity Address, Address Line Two | Building 3 |
| Entity Address, Address Line Three | Suite 700 |
| Entity Address, City or Town | Atlanta |
| Entity Address, State or Province | GA |
| Entity Address, Postal Zip Code | 30305 |
| City Area Code | 770 |
| Local Phone Number | 554-3545 |
| Title of 12(b) Security | Common Stock |
| Trading Symbol | DLHC |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000785557 |
| Amendment Flag | false |
