| Document and Entity Information | May 30, 2023 |
| Cover [Abstract] | |
| Entity Registrant Name | CITIZENS FINANCIAL SERVICES INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000739421 |
| Document Type | 8-K |
| Document Period End Date | May 30, 2023 |
| Entity Incorporation State Country Code | PA |
| Entity File Number | 001-41410 |
| Entity Tax Identification Number | 23-2265045 |
| Entity Address, Address Line One | 15 S Main St. |
| Entity Address, City or Town | Mansfield |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 16933 |
| City Area Code | (570) |
| Local Phone Number | 622-2121 |
| Written Communications | true |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, Par Value $1.00 Per Share |
| Trading Symbol | CZFS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
