| Document and Entity Information | Jul. 21, 2021 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jul. 21, 2021 |
| Entity File Number | 001-36388 |
| Entity Registrant Name | PEOPLES FINANCIAL SERVICES CORP. |
| Entity Incorporation, State or Country Code | PA |
| Entity Tax Identification Number | 23-2391852 |
| Entity Address, Address Line One | 150 North Washington Avenue |
| Entity Address, City or Town | Scranton |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 18503-1848 |
| City Area Code | 570 |
| Local Phone Number | 346-7741 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $2.00 par value |
| Trading Symbol | PFIS |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001056943 |
| Amendment Flag | false |
