| Document And Entity Information - USD ($) | 12 Months Ended | ||
| Dec. 31, 2022 | Feb. 28, 2023 | Jun. 30, 2022 | |
| Document Information [Line Items] | |||
| Entity, Registrant Name | Farmers and Merchants Bancshares, Inc. | ||
| Document, Type | 10-K/A | ||
| Document, Annual Report | true | ||
| Document, Period End Date | Dec. 31, 2022 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Document, Fiscal Period Focus | FY | ||
| Document, Fiscal Year Focus | 2022 | ||
| Document, Transition Report | false | ||
| Entity, File Number | 000-55756 | ||
| Entity, Incorporation, State or Country Code | MD | ||
| Entity, Tax Identification Number | 81-3605835 | ||
| Entity, Address, Address Line One | 4510 Lower Beckleysville Road, Suite H | ||
| Entity, Address, City or Town | Hampstead | ||
| Entity, Address, State or Province | MD | ||
| Entity, Address, Postal Zip Code | 21074 | ||
| City Area Code | 410 | ||
| Local Phone Number | 374-1510 | ||
| Title of 12(g) Security | Common stock, par value $.01 per share | ||
| 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 | $ 61,560,092 | ||
| Entity, Common Stock Shares, Outstanding | 3,071,214 | ||
| Auditor Name | Yount, Hyde & Barbour, P.C | ||
| Auditor Firm ID | 613 | ||
| Auditor Location | Richmond, VA | ||
| Amendment Description | This Amendment No. 1 on Form 10-K/A to the Annual Report of Farmers and Merchants Bancshares, Inc. on Form 10-K for the year ended December 31, 2022, which was initially filed with the Securities and Exchange Commission (the “SEC”) on March 10, 2023 (the “Original Report”), is being filed to amend Item 15 of Part IV of the Original Report to correct typographical errors in the titles of Exhibit 10.1 and Exhibit 10.2 and to add Exhibit 10.9. Pursuant to Rule 12b-15 under the Securities Exchange Act of 1934, as amended, new certifications by Farmers and Merchants Bancshares, Inc.’s principal executive officer and principal financial officer are filed or furnished with this Amendment No. 1 as Exhibits 31.1, 31.2, and 32.1. Except as expressly provided above, this Amendment No. 1 on Form 10-K/A speaks as of the date of the Original Report and Farmers and Merchants Bancshares, Inc. has not updated the disclosures contained in any item thereof to speak as of a later date. All information contained in this Amendment No. 1 on Form 10-K/A is subject to updating and supplementing as provided in Farmers and Merchants Bancshares, Inc.’s reports filed with the SEC subsequent to the date on which the Original Report was filed. | ||
| Amendment Flag | true | ||
| Entity, Central Index Key | 0001698022 |
