| Cover - USD ($) $ in Thousands | 12 Months Ended | ||
| Dec. 31, 2020 | Feb. 25, 2021 | Jun. 30, 2020 | |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Document Annual Report | true | ||
| Document Transition Report | false | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity File Number | 1-7234 | ||
| Entity Registrant Name | GP STRATEGIES CORPORATION | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Tax Identification Number | 52-0845774 | ||
| Entity Address, Address Line One | 70 Corporate Center | ||
| Entity Address, Postal Zip Code | 21044 | ||
| Entity Address, State or Province | MD | ||
| Entity Address, City or Town | Columbia | ||
| Entity Address, Address Line Two | 11000 Broken Land Parkway, Suite 300, | ||
| City Area Code | (443) | ||
| Local Phone Number | 367-9600 | ||
| Title of 12(b) Security | Common Stock, $.01 par value | ||
| Trading Symbol | GPX | ||
| 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 | Accelerated Filer | ||
| Entity Small Business | false | ||
| Entity Emerging Growth Company | false | ||
| ICFR Auditor Attestation Flag | true | ||
| Entity Public Float | $ 109,684 | ||
| Entity Shell Company | false | ||
| Entity Common Stock, Shares Outstanding | 17,349,122 | ||
| Amendment Flag | true | ||
| Document Fiscal Year Focus | 2020 | ||
| Document Fiscal Period Focus | FY | ||
| Entity Central Index Key | 0000070415 | ||
| Document Period End Date | Dec. 31, 2020 | ||
| Amendment Description | References in this report to “GP Strategies,” the “Company,” “we” and “our” are to GP Strategies Corporation and its subsidiaries, collectively. This Amendment No. 1 on Form 10-K/A (the “Amendment”) amends our annual report on Form 10-K for the year ended December 31, 2020, originally filed on March 12, 2021 (the “Original Filing”). We are filing this Amendment to include the information required by Part III and not included in the Original Filing as we will not file our definitive proxy statement within 120 days of the end of our fiscal year ended December 31, 2020. In addition, in connection with the filing of this Amendment and pursuant to the rules of the Securities and Exchange Commission (“SEC”), we are including with this Amendment certain currently dated certifications. Accordingly, Item 15 of Part IV has also been amended to reflect the filing of these currently dated certifications. |
