| Document And Entity Information | Apr. 29, 2021 |
| Document And Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Apr. 29, 2021 |
| Entity Registrant Name | Evans Bancorp, Inc. |
| Entity Incorporation, State or Country Code | NY |
| Entity File Number | 001-35021 |
| Entity Tax Identification Number | 16-1332767 |
| Entity Address, Address Line One | 6460 Main Street |
| Entity Address, City or Town | Williamsville |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 14221 |
| City Area Code | 716 |
| Local Phone Number | 926-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.50 par value |
| Trading Symbol | EVBN |
| Security Exchange Name | NYSEAMER |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0000842518 |
