Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 24, 2021	Jun. 30, 2020
Entity Information [Line Items]
Document Annual Report	true
Entity File Number	1-9047
Entity Address, Address Line One	2036 Washington Street,
Document Transition Report	false
Entity Incorporation, State or Country Code	MA
Entity Registrant Name	Independent Bank Corp
City Area Code	(781)
Local Phone Number	878-6100
Entity Central Index Key	0000776901
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 2,184,109,691
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		33,018,461
Entity Address, City or Town	Hanover,
Entity Tax Identification Number	04-2870273
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02339
Documents Incorporated by Reference	Portions of the Registrant’s definitive proxy statement for its 2021 Annual Meeting of Shareholders are incorporated into Part III, Items 10-14 of this Annual Report on Form 10-K. The 2021 definitive proxy statement will be filed within 120 days of December 31, 2020.
Current Fiscal Year End Date	--12-31
Mailing Address [Member]
Entity Information [Line Items]
Entity Address, Address Line One	288 Union Street,
Entity Address, City or Town	Rockland,
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02370
NASDAQ/NGS (GLOBAL SELECT MARKET) [Member]
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	INDB
Security Exchange Name	NASDAQ