| Cover | Aug. 19, 2020 | Feb. 27, 2020 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Aug. 19, 2020 | |
| 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 | false | |
| 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 |
