Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Feb. 26, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	000-16772
Entity Registrant Name	PEOPLES BANCORP INC.
Entity Incorporation, State or Country Code	OH
Entity Tax Identification Number	31-0987416
Entity Address, Address Line One	138 Putnam Street, P.O. 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
Title of 12(b) Security	Common shares, without par value
Trading Symbol	PEBO
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		19,623,956
Entity Central Index Key	0000318300
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 404,671
ICFR Auditor Attestation Flag	true