XML 136 R113.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Fair value disclosure only table (Details) - USD ($) $ in Thousands | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Assets, Fair Value Disclosure [Abstract] |  |  |
Debt Securities, Held-to-maturity |  | $ 1,434,956 | $ 1,569,107
Securities held to maturity, fair value |  | 1,291,801 | 1,417,608
Federal Home Loan Bank Stock |  | 31,573 | 43,557
Bank Owned Life Insurance |  | 303,965 | 297,387
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Federal Home Loan Bank borrowings |  | 638,514 | 1,105,541
Subordinated Debt |  | 0 | 49,980
Reported Value Measurement |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Loans, net of allowance for loan losses |  | 14,294,628 | 14,106,967
Estimate of Fair Value Measurement |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Loans, net of allowance for loan losses | [1] | 13,213,596 | 13,079,368
Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Financial Liabilities Book Value |  | 12,558,632 | 12,684,068
Accrued Liabilities, Fair Value Disclosure | [2] | 12,558,632 | 12,684,068
Bank Time Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Financial Liabilities Book Value |  | 2,747,346 | 2,181,479
Accrued Liabilities, Fair Value Disclosure | [3] | 2,739,606 | 2,166,573
Federal Home Loan Bank Advances [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Federal Home Loan Bank borrowings |  | 638,514 | 1,105,541
Federal Home Loan Bank Borrowings, Fair Value Disclosure | [3] | 638,489 | 1,103,845
Junior Subordinated Debt [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Junior subordinated debentures (less unamortized debt issuance costs of $28 and $30) |  | 62,860 | 62,858
Accrued Liabilities, Fair Value Disclosure | [4] | 61,661 | 58,911
Subordinated Debt [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Subordinated Debt |  |  | 49,980
Accrued Liabilities, Fair Value Disclosure | [3] |  | 49,613
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Estimate of Fair Value Measurement |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Loans, net of allowance for loan losses |  | 0 | 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 0 | 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Bank Time Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 0 | 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Federal Home Loan Bank Advances [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Federal Home Loan Bank Borrowings, Fair Value Disclosure |  | 0 | 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Junior Subordinated Debt [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 0 | 0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Subordinated Debt [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  |  | 0
Significant Other Observable Inputs (Level 2) [Member] | Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 12,558,632 | 12,684,068
Significant Other Observable Inputs (Level 2) [Member] | Bank Time Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 2,739,606 | 2,166,573
Significant Other Observable Inputs (Level 2) [Member] | Federal Home Loan Bank Advances [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Federal Home Loan Bank Borrowings, Fair Value Disclosure |  | 638,489 | 1,103,845
Significant Other Observable Inputs (Level 2) [Member] | Junior Subordinated Debt [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 61,661 | 58,911
Significant Unobservable Inputs (Level 3) [Member] | Estimate of Fair Value Measurement |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Loans, net of allowance for loan losses |  | 13,213,596 | 13,079,368
Significant Unobservable Inputs (Level 3) [Member] | Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 0 | 0
Significant Unobservable Inputs (Level 3) [Member] | Bank Time Deposits [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 0 | 0
Significant Unobservable Inputs (Level 3) [Member] | Federal Home Loan Bank Advances [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Federal Home Loan Bank Borrowings, Fair Value Disclosure |  | 0 | 0
Significant Unobservable Inputs (Level 3) [Member] | Junior Subordinated Debt [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  | 0 | 0
Significant Unobservable Inputs (Level 3) [Member] | Subordinated Debt [Member] |  |  |
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Accrued Liabilities, Fair Value Disclosure |  |  | 49,613
US Government Agencies Debt Securities [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value | [5] |  | 28,408
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Debt Securities, Held-to-maturity |  |  | 29,521
US Government Agencies Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  |  | 0
US Government Agencies Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  |  | 28,408
US Government Agencies Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  |  | 0
US Treasury Securities [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value | [5] | 93,022 | 91,535
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Debt Securities, Held-to-maturity |  | 100,791 | 100,712
US Treasury Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
US Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 93,022 | 91,535
US Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value | [5] | 726,362 | 763,728
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Debt Securities, Held-to-maturity |  | 788,470 | 829,431
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 726,362 | 763,728
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
Collateralized Mortgage Obligations [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value | [5] | 357,684 | 407,911
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Debt Securities, Held-to-maturity |  | 422,827 | 477,517
Collateralized Mortgage Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
Collateralized Mortgage Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 357,684 | 407,911
Collateralized Mortgage Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
Single Issuer Trust Preferred Securities Issued By Banks [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value | [5] |  | 1,373
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Debt Securities, Held-to-maturity |  |  | 1,500
Single Issuer Trust Preferred Securities Issued By Banks [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  |  | 0
Single Issuer Trust Preferred Securities Issued By Banks [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  |  | 1,373
Single Issuer Trust Preferred Securities Issued By Banks [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  |  | 0
Small Business Administration Pooled Securities [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value | [5] | 114,733 | 124,653
Liabilities, Fair Value Disclosure [Abstract] |  |  |
Debt Securities, Held-to-maturity |  | 122,868 | 130,426
Small Business Administration Pooled Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
Small Business Administration Pooled Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 114,733 | 124,653
Small Business Administration Pooled Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Securities held to maturity, fair value |  | 0 | 0
Investment in Federal Home Loan Bank Stock [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Federal Home Loan Bank Stock |  | 31,573 | 43,557
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure | [6] | 31,573 | 43,557
Investment in Federal Home Loan Bank Stock [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure |  | 0 | 0
Investment in Federal Home Loan Bank Stock [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure |  | 31,573 | 43,557
Investment in Federal Home Loan Bank Stock [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure |  | 0 | 0
Cash Surrender Value [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Bank Owned Life Insurance |  | 303,965 | 297,387
Cash Surrender Value, Fair Value Disclosure | [7] | 303,965 | 297,387
Cash Surrender Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Cash Surrender Value, Fair Value Disclosure |  | 0 | 0
Cash Surrender Value [Member] | Significant Other Observable Inputs (Level 2) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Cash Surrender Value, Fair Value Disclosure |  | 303,965 | 297,387
Cash Surrender Value [Member] | Significant Unobservable Inputs (Level 3) [Member] |  |  |
Assets, Fair Value Disclosure [Abstract] |  |  |
Cash Surrender Value, Fair Value Disclosure |  | $ 0 | $ 0
[1] | 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.
[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 by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities.
[4] | Fair value was determined based upon market prices of securities with similar terms and maturities.
[5] | 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.
[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 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 -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(20)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + 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 -Topic 942 -SubTopic 470 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478878/942-470-45-1 + 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 -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + 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 Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2)(i) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (bbb)(1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_CashSurrenderValueFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 3B -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-5 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityExcludingAccruedInterestBeforeAllowanceForCreditLoss
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://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(13)(3)(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + 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 -Topic 942 -SubTopic 325 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477974/942-325-45-1 + Details
Name: | us-gaap_FederalHomeLoanBankStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-7A Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 14 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-14 + 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://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2E -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2E Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (aa) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481800/320-10-50-5A Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 + 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 Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482106/820-10-50-2 + 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 -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + 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 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://www.xbrl.org/2009/role/commonPracticeRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_LoansReceivableFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -SubTopic 10 -Topic 210 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(19)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 944 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)(a)(2)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_SubordinatedDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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_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=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: |