| Document And Entity Information - USD ($) | Dec. 31, 2021 | Apr. 08, 2022 | Jun. 30, 2021 |
| Document Information [Line Items] | |||
| Entity, Registrant Name | SPAR GROUP, INC. | ||
| Document, Type | 10-K/A | ||
| Document, Annual Report | true | ||
| Document, Period End Date | Dec. 31, 2021 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Document, Fiscal Period Focus | FY | ||
| Document, Fiscal Year Focus | 2021 | ||
| Document, Transition Report | false | ||
| Entity, File Number | 0-27408 | ||
| Entity, Incorporation, State or Country Code | DE | ||
| Entity, Tax Identification Number | 33-0684451 | ||
| Entity, Address, Address Line One | 1910 Opdyke Court | ||
| Entity, Address, City or Town | Auburn Hills | ||
| Entity, Address, State or Province | MI | ||
| Entity, Address, Postal Zip Code | 48326 | ||
| City Area Code | 248 | ||
| Local Phone Number | 364-7727 | ||
| Title of 12(b) Security | Common Stock, par value $.01 per share | ||
| Trading Symbol | SGRP | ||
| Security Exchange Name | NASDAQ | ||
| Entity, Well-known Seasoned Issuer | No | ||
| Entity, Voluntary Filers | No | ||
| Entity, Current Reporting Status | Yes | ||
| Entity, Interactive Data, Current | Yes | ||
| Entity, Filer Category | Non-accelerated Filer | ||
| Entity, Small Business | true | ||
| Entity, Emerging Growth Company | false | ||
| ICFR Auditor Attestation Flag | false | ||
| Entity, Shell Company | false | ||
| Entity, Public Float | $ 13,000,000 | ||
| Entity, Common Stock Shares, Outstanding | 21,845,414 | ||
| Amendment Description | SPAR Group, Inc. (the "Corporation" or "SGRP", and together with its subsidiaries, the "Company") is filing this Amendment No. 1 on Form 10-K/A (this "Amendment") to amend SGRP's Annual Report on Form 10-K for the year ended December 31, 2021 ("Form 10-K"), originally filed with the Securities and Exchange Commission (the "SEC") on April 15, 2022, to include the information required by Part III of our Form 10-K and to make corresponding changes in the table of contents. This information was previously omitted from our Form 10-K in reliance on General Instruction G(3) to Form 10-K, which permits the information in the above referenced items to be incorporated in our Form 10-K by reference from our definitive proxy statement if such statement is filed no later than 120 days after our fiscal year-end. We are filing this Amendment to include Part III information in our Form 10-K because a definitive proxy statement containing such information will not be filed within that period. References to the Annual Report in Form 10-K and in this Amendment shall mean SGRP's 10-K as amended by this Amendment. | ||
| Auditor Name | BDO USA, LLP | ||
| Auditor Location | Troy, Michigan | ||
| Auditor Firm ID | 243 | ||
| Amendment Flag | true | ||
| Entity, Central Index Key | 0001004989 |
