XML 64 R53.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Basis of Presentation (Details) - USD ($) $ in Thousands | Jan. 01, 2023 | Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | --- | --- | ---
Accounting Policies [Abstract] |  |  |  |
FHLB Stock |  | $ 12,762 | $ 12,762 |
FRB Stock |  | 2,400 | 2,400 |
Other |  | 686 | 584 |
Total |  | 15,848 | 15,746 |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance |  | 13,108 | 9,850 | $ 9,103
Off-Balance-Sheet, Credit Loss, Liability |  | 315 |  |
Commercial [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance |  | 968 | 860 |
Commercial Real Estate |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance |  | 5,878 | 461 |
Agricultural [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance |  | 270 | 577 | 289
Residential Mortgage |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance |  | 4,336 | 617 | 747
Unallocated Financing Receivables [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance |  | 0 | $ 6,374 | $ 5,419
Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | $ 12,594 |  |  |
Cumulative Effect, Period of Adoption, Adjusted Balance | Commitments to Extend Credit |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Off-Balance-Sheet, Credit Loss, Liability | 315 |  |  |
Cumulative Effect, Period of Adoption, Adjusted Balance | Commercial [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 802 |  |  |
Cumulative Effect, Period of Adoption, Adjusted Balance | Commercial Real Estate |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 5,993 |  |  |
Cumulative Effect, Period of Adoption, Adjusted Balance | Agricultural [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 330 |  |  |
Cumulative Effect, Period of Adoption, Adjusted Balance | Residential Mortgage |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 4,152 |  |  |
Cumulative Effect, Period of Adoption, Adjusted Balance | Consumer Loan |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 1,317 |  |  |
Cumulative Effect, Period of Adoption, Adjusted Balance | Unallocated Financing Receivables [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 0 |  |  |
Accounting Standards Update 2016-13 |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 2,744 | 2,744 |  |
Accounting Standards Update 2016-13 | Commitments to Extend Credit |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | (249) |  |  |
Off-Balance-Sheet, Credit Loss, Liability | 315 |  |  |
Accounting Standards Update 2016-13 | Loans Receivable |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | (2,168) |  |  |
Accounting Standards Update 2016-13 | Commercial [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | (58) | (58) |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | 46 |  |  |
Accounting Standards Update 2016-13 | Commercial Real Estate |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 5,532 | 5,532 |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | (4,370) |  |  |
Accounting Standards Update 2016-13 | Agricultural [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | (247) | (247) |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | 195 |  |  |
Accounting Standards Update 2016-13 | Residential Mortgage |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 3,535 | 3,535 |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | (2,793) |  |  |
Accounting Standards Update 2016-13 | Consumer Loan |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 356 |  |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | (281) |  |  |
Accounting Standards Update 2016-13 | Unallocated Financing Receivables [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | (6,374) | $ (6,374) |  |
Financing Receivable, Allowance for Credit Losses, Effect of Change in Method | 5,035 |  |  |
Pre Adoption Allowance |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 9,850 |  |  |
Pre Adoption Allowance | Commitments to Extend Credit |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Off-Balance-Sheet, Credit Loss, Liability | 0 |  |  |
Pre Adoption Allowance | Commercial [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 860 |  |  |
Pre Adoption Allowance | Commercial Real Estate |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 461 |  |  |
Pre Adoption Allowance | Agricultural [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 577 |  |  |
Pre Adoption Allowance | Residential Mortgage |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 617 |  |  |
Pre Adoption Allowance | Consumer Loan |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | 961 |  |  |
Pre Adoption Allowance | Unallocated Financing Receivables [Member] |  |  |  |
Financing Receivable, Nonaccrual [Line Items] |  |  |  |
Allowance for loan losses, Ending Balance | $ 6,374 |  |  |

X
- Definition Equity Method And Other Investments + References No definition available. + Details
Name: | isba_EquityMethodAndOtherInvestments
Namespace Prefix: | isba_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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//1943274/2147481026/942-325-45-1 + Details
Name: | us-gaap_FederalHomeLoanBankStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Federal Reserve Bank stock represents an equity interest in the Federal Reserve Bank. 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//1943274/2147481026/942-325-45-1 + Details
Name: | us-gaap_FederalReserveBankStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(4)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (1) -Publisher SEC Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (a) -Subparagraph (3) -Publisher SEC Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph (c) -Publisher SEC Reference 5: http://www.xbrl.org/2003/role/disclosureRef -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 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 210 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(7)(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(1) -SubTopic 10 -Topic 310 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The effect of a change in method or methods for calculating the allowance for credit losses on the current period provision. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesEffectOfChangeInMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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 Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1405 -Paragraph c -Publisher SEC + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479344/326-20-45-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 460 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482454/460-10-45-1 + Details
Name: | us-gaap_OffBalanceSheetCreditLossLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of investments classified as other. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(12)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 + Details
Name: | us-gaap_OtherInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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

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

X
- Details
Name: | srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommitmentsToExtendCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | srt_CumulativeEffectPeriodOfAdoptionAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_LoansReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CumulativeEffectPeriodOfAdoptionAxis=isba_PreAdoptionAllowanceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |