| Cover Page - USD ($) | 12 Months Ended | | |
| Dec. 31, 2021 | Mar. 01, 2022 | Jul. 02, 2021 |
| Cover [Abstract] | | | |
| Trading Symbol | HCKT | | |
| Entity Registrant Name | Hackett Group, Inc. | | |
| Entity Central Index Key | 0001057379 | | |
| Document Type | 10-K/A | | |
| Document Period End Date | Dec. 31, 2021 | | |
| Amendment Flag | true | | |
| Document Fiscal Year Focus | 2021 | | |
| Document Fiscal Period Focus | FY | | |
| Current Fiscal Year End Date | --12-31 | | |
| Entity Filer Category | Accelerated Filer | | |
| Entity Well-known Seasoned Issuer | No | | |
| Entity Voluntary Filers | No | | |
| Entity Small Business | false | | |
| Entity Shell Company | false | | |
| Entity Emerging Growth Company | false | | |
| Entity Current Reporting Status | Yes | | |
| Entity Public Float | | | $ 400,733,653 |
| Entity Common Stock, Shares Outstanding | | 31,614,513 | |
| Title of 12(b) Security | Common Stock, par value $.001 per share | | |
| Security Exchange Name | NASDAQ | | |
| Entity Interactive Data Current | Yes | | |
| 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 | | |
| Entity Incorporation, State or Country Code | FL | | |
| Document Annual Report | true | | |
| Document Transition Report | false | | |
| ICFR Auditor Attestation Flag | true | | |
| Auditor Name | RSM US LLP | | |
| Auditor Firm ID | 49 | | |
| Auditor Location | Miami, FL | | |
| Documents Incorporated by Reference | Part III of this Annual Report on Form 10-K | | |
| Amendment Description | The Hackett Group, Inc. and its subsidiaries (the “Company,” “we,” “us,” or “our”) is filing this Amendment on Form 10-K/A (this “Form 10-K/A”) to its Annual Report on Form 10-K for the fiscal year ended December 31, 2021, originally filed with the Securities and Exchange Commission (the “SEC”) on March 4, 2022 (the “Original Filing”), to amend and restate Part II, Item 9A Controls and Procedures and to file certain exhibits. In the third quarter of 2022, the Company reconsidered the guidance under ASC 280, Segment Reporting in response to comment letters from and discussions with the staff of the SEC. As a result of this reconsideration, the Company concluded that its prior determination that the Company had one operating segment and one reportable segment under ASC 280 was an error. As a result of the incorrect evaluation of ASC 280, the Company omitted certain segment related disclosures in its historical financial statements, including the financial statements included in the Original Filing. However, the Company determined that the omission of the required segment disclosures did not result in a material misstatement of the Company’s financial statements and, accordingly, it does not need to restate its previously issued financial statements contained in the Original Filing or in any of its Quarterly Reports on Form 10-Q. As described in more detail under Part II, Item 9A Controls and Procedures, the Company intends to begin reporting multiple reporting segments beginning with its Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2022. The Company also determined that a material weakness in its internal control over financial reporting related to segment reporting existed as of December 31, 2021. As a result, the Company is amending and restating Part II, Item 9A Controls and Procedures in this Form 10-K/A to: (a) update our conclusions regarding the effectiveness of our disclosure controls and procedures and our internal control over financial reporting as a result of the material weakness, and (b) include the restated attestation report of RSM US LLP, our independent registered public accounting firm (PCAOB ID: 49), regarding our internal control over financial reporting as a result of the material weakness. For a description of the material weakness and our remedial actions, please see Part II, Item 9A Controls and Procedures of this Form 10-K/A. As required by Rule 12b-15 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), the certifications required by Rule 13a-14(a) under the Exchange Act are also being filed as exhibits to this Form 10-K/A. This Form 10-K/A should be read in conjunction with the Original Filing, which continues to speak as of the date of the Original Filing. Except as specifically noted above, this Form 10-K/A does not modify or update disclosures in the Original Filing. Accordingly, this Form 10-K/A does not reflect events occurring after the filing of the Original Filing or modify or update any related or other disclosures, other than those discussed above. No other portions of the Original Filing were changed. | | |
