Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Nov. 10, 2022
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Entity File Number	001-39285
Document Period End Date	Sep. 30, 2022
Entity Registrant Name	Partners Bancorp
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	52-1559535
Entity Address, Address Line One	2245 Northwood Drive
Entity Address, City or Town	Salisbury
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	21801
City Area Code	410
Local Phone Number	548-1100
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	PTRS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		17,961,699
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000832090
Amendment Flag	false