XML 99 R79.htm IDEA: XBRL DOCUMENT
v3.20.2

Fair Value Measurements (Details 3) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
ASSETS |  |  |
Debt Securities, Held-to-maturity |  | $ 659,573 | $ 740,806
Held to Maturity, Fair Value, Total |  | 690,467 | 753,263
Loans, net of allowance for credit losses(b) |  | 9,289,568 | 8,805,899
Federal Home Loan Bank Stock |  | 15,090 | 14,424
Bank Owned Life Insurance |  | 199,453 | 197,372
LIABILITIES |  |  |
Federal Home Loan Bank borrowings(f) |  | 145,765 | 115,748
Long-term Debt | [1] | 37,447 | 74,906
Long-term Debt, Fair Value | [1] | 36,448 | 72,219
Subordinated Debt |  | 49,672 | 49,601
Deposits [Member] |  |  |
LIABILITIES |  |  |
Time certificates of deposits(f) | [2] | 9,792,667 | 7,752,052
Accrued Liabilities, Fair Value Disclosure | [2] | 9,792,667 | 7,752,052
Time certificates of deposits(f) |  |  |
LIABILITIES |  |  |
Time certificates of deposits(f) | [1] | 1,058,641 | 1,395,315
Accrued Liabilities, Fair Value Disclosure | [1] | 1,065,818 | 1,396,760
Federal Home Loan Bank borrowings(f) |  |  |
LIABILITIES |  |  |
Federal Home Loan Bank borrowings(f) | [1] | 145,765 | 115,748
Federal Home Loan Bank Borrowings, Fair Value Disclosure | [1] | 145,975 | 115,881
Junior subordinated debentures(g) |  |  |
LIABILITIES |  |  |
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust | [3] | 62,850 | 62,848
Accrued Liabilities, Fair Value Disclosure | [3] | 67,883 | 65,603
Subordinated debentures(f) |  |  |
LIABILITIES |  |  |
Subordinated Debt | [1] | 49,672 | 49,601
Accrued Liabilities, Fair Value Disclosure | [1] | 47,173 | 52,870
Quoted Prices in Active Markets for Identical Assets (Level 1) | Long-term Debt [Member] |  |  |
LIABILITIES |  |  |
Long-term Debt, Fair Value | [1] | 0 | 0
Significant Other Observable Inputs (Level 2) | Deposits [Member] |  |  |
LIABILITIES |  |  |
Accrued Liabilities, Fair Value Disclosure | [2] | 9,792,667 | 7,752,052
Significant Other Observable Inputs (Level 2) | Time certificates of deposits(f) |  |  |
LIABILITIES |  |  |
Accrued Liabilities, Fair Value Disclosure | [1] | 1,065,818 | 1,396,760
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank borrowings(f) |  |  |
LIABILITIES |  |  |
Federal Home Loan Bank Borrowings, Fair Value Disclosure | [1] | 145,975 |
Accrued Liabilities, Fair Value Disclosure | [1] |  | 115,881
Significant Other Observable Inputs (Level 2) | Long-term Debt [Member] |  |  |
LIABILITIES |  |  |
Long-term Debt, Fair Value | [1] | 36,448 | 72,219
Significant Other Observable Inputs (Level 2) | Junior subordinated debentures(g) |  |  |
LIABILITIES |  |  |
Accrued Liabilities, Fair Value Disclosure | [3] | 67,883 | 65,603
Significant Unobservable Inputs (Level 3) | Long-term Debt [Member] |  |  |
LIABILITIES |  |  |
Long-term Debt, Fair Value | [1] | 0 | 0
Significant Unobservable Inputs (Level 3) | Subordinated debentures(f) |  |  |
LIABILITIES |  |  |
Accrued Liabilities, Fair Value Disclosure | [1] | 47,173 | 52,870
U.S. Government agency securities |  |  |
ASSETS |  |  |
Debt Securities, Held-to-maturity | [4] |  | 12,874
Held to Maturity, Fair Value, Total | [4] |  | 12,997
U.S. Government agency securities | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] |  | 12,997
U.S. Treasury securities |  |  |
ASSETS |  |  |
Debt Securities, Held-to-maturity | [4] | 4,021 | 4,032
Held to Maturity, Fair Value, Total | [4] | 4,100 | 4,053
U.S. Treasury securities | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] | 4,100 | 4,053
Agency mortgage-backed securities |  |  |
ASSETS |  |  |
Debt Securities, Held-to-maturity | [4] | 388,106 | 397,414
Held to Maturity, Fair Value, Total | [4] | 407,793 | 405,802
Agency mortgage-backed securities | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] | 407,793 | 405,802
Agency collateralized mortgage obligations |  |  |
ASSETS |  |  |
Debt Securities, Held-to-maturity | [4] | 237,380 | 293,662
Held to Maturity, Fair Value, Total | [4] | 246,937 | 297,314
Agency collateralized mortgage obligations | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] | 246,937 | 297,314
Single issuer trust preferred securities issued by banks |  |  |
ASSETS |  |  |
Debt Securities, Held-to-maturity | [4] | 1,500 | 1,500
Held to Maturity, Fair Value, Total | [4] | 1,498 | 1,490
Single issuer trust preferred securities issued by banks | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] | 1,498 | 1,490
Small Business Administration Pooled Securities [Member] |  |  |
ASSETS |  |  |
Debt Securities, Held-to-maturity | [4] | 28,566 | 31,324
Held to Maturity, Fair Value, Total | [4] | 30,139 | 31,607
Small Business Administration Pooled Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] | 0 | 0
Small Business Administration Pooled Securities [Member] | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] | 30,139 | 31,607
Small Business Administration Pooled Securities [Member] | Significant Unobservable Inputs (Level 3) |  |  |
ASSETS |  |  |
Held to Maturity, Fair Value, Total | [4] | 0 | 0
Loans, net of allowance for credit losses(b) |  |  |
ASSETS |  |  |
Loans, net of allowance for credit losses(b) | [5] | 9,232,908 | 8,780,384
Loans Receivable, Fair Value Disclosure | [5] | 9,185,023 | 8,613,635
Loans, net of allowance for credit losses(b) | Significant Unobservable Inputs (Level 3) |  |  |
ASSETS |  |  |
Loans Receivable, Fair Value Disclosure | [5] | 9,185,023 | 8,613,635
Investment in Federal Home Loan Bank Stock [Member] |  |  |
ASSETS |  |  |
Federal Home Loan Bank Stock | [6] | 15,090 | 14,424
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 15,090 | 14,424
Investment in Federal Home Loan Bank Stock [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
ASSETS |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 0 | 0
Investment in Federal Home Loan Bank Stock [Member] | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 15,090 | 14,424
Investment in Federal Home Loan Bank Stock [Member] | Significant Unobservable Inputs (Level 3) |  |  |
ASSETS |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 0 | 0
Cash Surrender Value [Member] |  |  |
ASSETS |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | 199,453 | 197,372
Bank Owned Life Insurance | [7] | 199,453 | 197,372
Cash Surrender Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |  |
ASSETS |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | 0 | 0
Cash Surrender Value [Member] | Significant Other Observable Inputs (Level 2) |  |  |
ASSETS |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | 199,453 | 197,372
Cash Surrender Value [Member] | Significant Unobservable Inputs (Level 3) |  |  |
ASSETS |  |  |
Cash Surrender Value, Fair Value Disclosure | [7] | $ 0 | $ 0
[1] | Fair value was determined by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities.
[2] | Fair value of demand deposits, savings and interest checking accounts and money market deposits is the amount payable on demand at the reporting date.
[3] | Fair value was determined based upon market prices of securities with similar terms and maturities.
[4] | The fair values presented are based on quoted market prices, where available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments and/or discounted cash flow analysis.
[5] | Fair value of loans is measured using the exit price valuation method, determined primarily by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows, while incorporating liquidity and credit assumptions. Additionally, this amount excludes individually assessed collateral dependent loans, which are deemed to be marked to fair value on a nonrecurring basis.
[6] | Federal Home Loan Bank stock has no quoted market value and is carried at cost; therefore the carrying amount approximates fair value.
[7] | Cash surrender value of life insurance policies is recorded at its cash surrender value (or the amount that can be realized upon surrender of the policy), therefore, carrying amount approximates fair value.

X
- Definition Financial liabilities book value. + References No definition available. + Details
Name: | indb_FinancialLiabilitiesBookValue
Namespace Prefix: | indb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of accrued expenses. + 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 210.5-02.20) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_AccruedLiabilitiesFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 + Details
Name: | us-gaap_AdvancesFromFederalHomeLoanBanks
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
Name: | us-gaap_BankOwnedLifeInsurance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of the amount that could be realized under a life insurance contract or contracts owned by the entity, commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI). + References No definition available. + Details
Name: | us-gaap_CashSurrenderValueFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of borrowing from Federal Home Loan Bank (FHLBank). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13(3)(a)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
Name: | us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 325 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809 + Details
Name: | us-gaap_FederalHomeLoanBankStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
Name: | us-gaap_HeldToMaturitySecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121645371&loc=SL120269820-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock. + References No definition available. + Details
Name: | us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
Name: | us-gaap_JuniorSubordinatedDebentureOwedToUnconsolidatedSubsidiaryTrust
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_LiabilitiesFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=121593590&loc=d3e4428-111522 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
Name: | us-gaap_LoansAndLeasesReceivableNetReportedAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -URI http://asc.fasb.org/subtopic&trid=2196772 + Details
Name: | us-gaap_LoansReceivableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 4: 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(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_LongTermDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
Name: | us-gaap_LongTermDebtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets. + 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(19)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 4: 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(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_SubordinatedDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_DepositsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_BankTimeDepositsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_FederalHomeLoanBankAdvancesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_JuniorSubordinatedDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_SubordinatedDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByLiabilityClassAxis=us-gaap_LongTermDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CollateralizedMortgageObligationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=indb_SingleIssuerTrustPreferredSecuritiesIssuedByBanksMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=indb_SmallBusinessAdministrationPooledSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=indb_LoansNetOfAllowanceForLoanLosesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_InvestmentInFederalHomeLoanBankStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CashSurrenderValueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |