XML 61 R42.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Loans, Allowance for Loan Losses and Credit Quality (Internal Risk-Rating Categories for the Commercial Portfolio) (Details) - USD ($) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2018 | Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items] |  |
Significant Advanced Considered For Risk Rating Change | $ 50,000 |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 4,637,962,000 | $ 4,539,256,000
Commercial and Industrial [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 1,003,780,000 | 888,528,000
Commercial Real Estate [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 3,132,491,000 | 3,116,561,000
Commercial Construction [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 352,491,000 | 401,797,000
Small Business [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 149,200,000 | 132,370,000
PASS [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 4,476,319,000 | 4,345,232,000
PASS [Member] | Commercial and Industrial [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 935,769,000 | 806,331,000
PASS [Member] | Commercial Real Estate [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 3,041,551,000 | 3,007,672,000
PASS [Member] | Commercial Construction [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 352,190,000 | 400,964,000
PASS [Member] | Small Business [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 146,809,000 | 130,265,000
POTENTIAL WEAKNESS [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 71,098,000 | 87,822,000
POTENTIAL WEAKNESS [Member] | Commercial and Industrial [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 17,655,000 | 16,563,000
POTENTIAL WEAKNESS [Member] | Commercial Real Estate [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 52,089,000 | 69,788,000
POTENTIAL WEAKNESS [Member] | Commercial Construction [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 301,000 | 0
POTENTIAL WEAKNESS [Member] | Small Business [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 1,053,000 | 1,471,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 85,190,000 | 99,516,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Commercial and Industrial [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 45,399,000 | 59,415,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Commercial Real Estate [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 38,453,000 | 38,637,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Commercial Construction [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 0 | 833,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Small Business [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 1,338,000 | 631,000
PARTIAL LOSS PROBABLE [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 5,355,000 | 6,686,000
PARTIAL LOSS PROBABLE [Member] | Commercial and Industrial [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 4,957,000 | 6,219,000
PARTIAL LOSS PROBABLE [Member] | Commercial Real Estate [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 398,000 | 464,000
PARTIAL LOSS PROBABLE [Member] | Commercial Construction [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 0 | 0
PARTIAL LOSS PROBABLE [Member] | Small Business [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 0 | 3,000
DEFINITE LOSS [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 0 | 0
DEFINITE LOSS [Member] | Commercial and Industrial [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 0 | 0
DEFINITE LOSS [Member] | Commercial Real Estate [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 0 | 0
DEFINITE LOSS [Member] | Commercial Construction [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | 0 | 0
DEFINITE LOSS [Member] | Small Business [Member] |  |
Internal risk-rating categories for the Company's commercial portfolio |  |
TOTAL | $ 0 | $ 0

X
- Definition Significant Advanced Considered For Risk Rating Change + References No definition available. + Details
Name: | indb_SignificantAdvancedConsideredForRiskRatingChange
Namespace Prefix: | indb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Summary of internal risk rating categories. + References No definition available. + Details
Name: | indb_SummaryOfInternalRiskRatingCategoriesAbstract
Namespace Prefix: | indb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_NotesReceivableNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=indb_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=indb_SmallBusinessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_PassMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=indb_PotentialWeaknessMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=indb_DefiniteWeaknessLossUnlikelyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=indb_PartialLossProbableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=indb_DefiniteLossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |