SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details Textual)	12 Months Ended
Dec. 31, 2016 USD ($) center branch	Dec. 31, 2015 USD ($)
Accounting Policies [Line Items]
Reserve for unfunded loan commitments \| $	$ 954,000	$ 1,400,000
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net \| $	$ 501,000	$ 568,000
Maximum [Member]
Accounting Policies [Line Items]
Lease option period	15 years
Loans Receivable [Member] \| Lender Concentration Risk [Member] \| Residential Building [Member]
Accounting Policies [Line Items]
Loans of nonresidential buildings to total loan portfolio	15.40%	15.00%
Full Service Retail Branch [Member] \| Bank [Member]
Accounting Policies [Line Items]
Number of branches \| branch	80
Limited Service Retail Branch [Member] \| Bank [Member]
Accounting Policies [Line Items]
Number of branches \| branch	3
Commercial Banking Center [Member] \| Bank [Member]
Accounting Policies [Line Items]
Number of centers	11
Investment Management Office [Member] \| Bank [Member]
Accounting Policies [Line Items]
Number of centers	5
Mortgage Lending Center [Member] \| Bank [Member]
Accounting Policies [Line Items]
Number of centers	1

[Line Items] for Accounting Policies [Table]

No definition available.

Name:	indb_AccountingPoliciesLineItems
Namespace Prefix:	indb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Lease Option Period

+ References

No definition available.

+ Details

Name:	indb_LeaseOptionPeriod
Namespace Prefix:	indb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Branches

+ References

No definition available.

+ Details

Name:	indb_NumberOfBranches
Namespace Prefix:	indb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of Centers

+ References

No definition available.

+ Details

Name:	indb_NumberOfCenters
Namespace Prefix:	indb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=64851502&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13537-108611

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of unamortized debt discount (premium) and debt issuance costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399

+ Details

Name:	us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18794-111554

+ Details

Name:	us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_LoansReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_LenderConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=indb_ResidentialBuildingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	indb_TypeOfOperationAxis=indb_FullServiceRetailBranchMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=indb_RocklandTrustCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	indb_TypeOfOperationAxis=indb_LimitedServiceRetailBranchMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	indb_TypeOfOperationAxis=indb_CommercialBankingCenterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	indb_TypeOfOperationAxis=indb_InvestmentManagementOfficeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	indb_TypeOfOperationAxis=indb_MortgageLendingCenterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: