FAIR VALUE MEASUREMENTS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets
Securities available for sale	$ 348,554us-gaap_AvailableForSaleSecurities	$ 356,862us-gaap_AvailableForSaleSecurities
Disposal Group, Including Discontinued Operation, Mortgage Loans	6,888us-gaap_LoansHeldForSaleMortgages	8,882us-gaap_LoansHeldForSaleMortgages
Total	22,390	16,697
Fair Value, Measurements, Recurring [Member]
Liabilities
Total recurring fair value measurements	350,180	356,314
Fair Value, Measurements, Recurring [Member] \| U.S. Government agency securities
Assets
Securities available for sale	41,486	40,449
Fair Value, Measurements, Recurring [Member] \| Agency mortgage-backed securities
Assets
Securities available for sale	217,678	234,591
Fair Value, Measurements, Recurring [Member] \| Agency collateralized mortgage obligations
Assets
Securities available for sale	63,035	58,153
Fair Value, Measurements, Recurring [Member] \| State, county, and municipal securities
Assets
Securities available for sale	5,223	5,412
Fair Value, Measurements, Recurring [Member] \| Single issuer trust preferred securities issued by banks and insurers
Assets
Securities available for sale	2,909	2,952
Fair Value, Measurements, Recurring [Member] \| Pooled trust preferred securities issued by banks and insurers
Assets
Securities available for sale	6,321	3,841
Fair Value, Measurements, Recurring [Member] \| Equity securities
Assets
Securities available for sale	11,902	11,464
Fair Value, Measurements, Recurring [Member] \| Loans held for sale
Assets
Disposal Group, Including Discontinued Operation, Mortgage Loans	6,888	8,882
Fair Value, Measurements, Recurring [Member] \| Derivative instruments
Assets
Total	22,688	16,965
Fair Value, Measurements, Recurring [Member] \| Derivative Instruments
Liabilities
Liabilities	27,950	26,395
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Liabilities
Total recurring fair value measurements	11,902	11,464
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| State, county, and municipal securities
Assets
Securities available for sale		0
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] \| Equity securities
Assets
Securities available for sale	11,902	11,464
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member]
Liabilities
Total recurring fair value measurements	331,957	341,009
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| U.S. Government agency securities
Assets
Securities available for sale	41,486	40,449
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Agency mortgage-backed securities
Assets
Securities available for sale	217,678	234,591
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Agency collateralized mortgage obligations
Assets
Securities available for sale	63,035	58,153
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| State, county, and municipal securities
Assets
Securities available for sale	5,223	5,412
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Single issuer trust preferred securities issued by banks and insurers
Assets
Securities available for sale	2,909	2,952
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Loans held for sale
Assets
Securities available for sale	6,888	8,882
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Derivative instruments
Assets
Total	22,688	16,965
Fair Value, Measurements, Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Derivative Instruments
Liabilities
Liabilities	27,950	26,395
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Liabilities
Total recurring fair value measurements	6,321	3,841
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| U.S. Government agency securities
Assets
Securities available for sale
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| State, county, and municipal securities
Assets
Securities available for sale		0
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Pooled trust preferred securities issued by banks and insurers
Assets
Securities available for sale	6,321	3,841
Fair Value, Measurements, Nonrecurring [Member]
Assets
Assets And Liabilities Fair Value Disclosure Nonrecurring	15,939	17,961
Fair Value, Measurements, Nonrecurring [Member] \| Collateral dependent impaired loans
Assets
Assets nonrecurring	8,196	10,328
Fair Value, Measurements, Nonrecurring [Member] \| Other real estate owned and other foreclosed assets
Assets
Assets nonrecurring	7,743	7,633
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Assets
Assets And Liabilities Fair Value Disclosure Nonrecurring	15,939	17,961
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Collateral dependent impaired loans
Assets
Assets nonrecurring	8,196	10,328
Fair Value, Measurements, Nonrecurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Other real estate owned and other foreclosed assets
Assets
Assets nonrecurring	$ 7,743	$ 7,633

Assets and liabilities, fair value disclosure nonrecurring.

No definition available.

Name:	indb_AssetsAndLiabilitiesFairValueDisclosureNonrecurring
Namespace Prefix:	indb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Assets and liabilities, fair value disclosure recurring.

+ References

No definition available.

+ Details

Name:	indb_AssetsAndLiabilitiesFairValueDisclosureRecurring
Namespace Prefix:	indb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ References

No definition available.

+ Details

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

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

+ Details

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

- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226000-175313

+ Details

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

- Details

Name:	us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregation of the liabilities reported on the balance sheet measured at fair value on a recurring basis by the entity.

+ References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosureRecurring
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount classified as mortgage loans attributable to disposal group held for sale or disposed of. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a)(3))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6490309&loc=d3e48678-111004

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Permanent Investor

-URI http://asc.fasb.org/extlink&oid=6520390

+ Details

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

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: