Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 05, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Entity File Number	001-13349
Entity Registrant Name	BAR HARBOR BANKSHARES
Entity Incorporation, State or Country Code	ME
Entity Tax Identification Number	01-0393663
Entity Address, Address Line One	PO Box 400
Entity Address, Address Line Two	82 Main Street
Entity Address, City or Town	Bar Harbor
Entity Address, State or Province	ME
Entity Address, Postal Zip Code	04609-0400
City Area Code	207
Local Phone Number	288-3314
Title of 12(b) Security	Common Stock, par value $2.00 per share
Trading Symbol	BHB
Security Exchange Name	NYSEAMER
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		14,986,786
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000743367
Amendment Flag	false