| Document and Entity Information | May 06, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001057379 |
| Document Type | 8-K |
| Document Period End Date | May 6, 2021 |
| Entity Registrant Name | Hackett Group, Inc. |
| Entity Incorporation, State or Country Code | FL |
| Entity File Number | 333-48123 |
| Entity Tax Identification Number | 65-0750100 |
| Entity Address, Address Line One | 1001 Brickell Bay Drive |
| Entity Address, Address Line Two | Suite 3000 |
| Entity Address, City or Town | Miami |
| Entity Address, State or Province | FL |
| Entity Address, Postal Zip Code | 33131 |
| City Area Code | 305 |
| Local Phone Number | 375-8005 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Title of 12(b) Security | Common Stock, par value $.001 per share |
| Trading Symbol | HCKT |
| Security Exchange Name | NASDAQ |
