| Cover Page - USD ($) $ in Millions | 12 Months Ended | ||
| Dec. 29, 2019 | Mar. 01, 2020 | Jun. 30, 2019 | |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Document Annual Report | true | ||
| Document Period End Date | Dec. 29, 2019 | ||
| Document Transition Report | false | ||
| Entity File Number | 001-37480 | ||
| Entity Registrant Name | UNIQUE FABRICATING, INC. | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Tax Identification Number | 46-1846791 | ||
| Entity Address, Address Line One | 800 Standard Parkway | ||
| 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 | 853-2333 | ||
| Title of 12(b) Security | Common Stock, par value $.001 per share | ||
| Trading Symbol | UFAB | ||
| Security Exchange Name | NYSEAMER | ||
| 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 | ||
| Entity Shell Company | false | ||
| Entity Common Stock, Shares Outstanding | 9,779,147 | ||
| Entity Public Float | $ 26.5 | ||
| Documents Incorporated by Reference | Portions of the registrant’s definitive Proxy Statement related to its Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10-K/A | ||
| Entity Central Index Key | 0001617669 | ||
| Amendment Flag | false | ||
| Current Fiscal Year End Date | --12-29 | ||
| Document Fiscal Year Focus | 2019 | ||
| Document Fiscal Period Focus | FY |
