Cover - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 01, 2021	Jun. 30, 2020
Document and Entity Information [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Annual Report	true
Document Transition Report	false
Entity File Number	001-33912
Entity Registrant Name	Enterprise Bancorp, Inc.
Entity Incorporation, State or Country Code	MA
Entity Tax Identification Number	04-3308902
Entity Address, Address Line One	222 Merrimack Street,
Entity Address, City or Town	Lowell,
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01852
City Area Code	(978)
Local Phone Number	459-9000
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	EBTC
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 233,944,867
Entity Common Stock, Shares Outstanding		11,957,927
Documents Incorporated by Reference	DOCUMENTS INCORPORATED BY REFERENCEPortions of the registrant’s definitive proxy statement for its annual meeting of stockholders to be held on May 4, 2021 are incorporated by reference in Part III of this Form 10-K.
Entity Central Index Key	0001018399
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY