| Cover | Oct. 19, 2020 |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 19, 2020 |
| Entity File Number | 0-13888 |
| Entity Registrant Name | CHEMUNG FINANCIAL CORPORATION |
| Entity Central Index Key | 0000763563 |
| Entity Tax Identification Number | 16-1237038 |
| Entity Incorporation, State or Country Code | NY |
| Entity Address, Address Line One | One Chemung Canal Plaza |
| Entity Address, City or Town | Elmira |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 14901 |
| City Area Code | 607 |
| Local Phone Number | 737-3711 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, par value $.01 per share |
| Trading Symbol | CHMG |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
