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.