| Cover | May 03, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | May 3, 2021 |
| Entity Registrant Name | PEOPLES BANCORP INC. |
| Entity Incorporation, State or Country Code | OH |
| Entity File Number | 000-16772 |
| Entity Tax Identification Number | 31-0987416 |
| Entity Address, Address Line One | 138 Putnam Street, PO Box 738 |
| Entity Address, City or Town | Marietta, |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 45750-0738 |
| City Area Code | (740) |
| Local Phone Number | 373-3155 |
| Written Communications | true |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common shares, without par value |
| Trading Symbol | PEBO |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000318300 |
| Amendment Flag | false |
