XML 70 R59.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Loans and ACL (Summary of Loan Composition) (Details) $ in Thousands | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
--- | --- | ---
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 1,349,463 | $ 1,264,173
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 1.0000 | 1.0000
Commercial and Industrial, Secured, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 189,186 | $ 161,895
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.1402 | 0.1280
Commercial and Industrial, Unsecured, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 20,552 | $ 16,533
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0152 | 0.0131
Commercial [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 209,738 | $ 178,428
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.1554 | 0.1411
Commercial Real Estate, Owner Occupied, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 180,636 | $ 192,117
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.1339 | 0.1520
Commercial Real Estate, Non-owner Occupied |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 216,292 | $ 204,091
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.1603 | 0.1614
Commercial Real Estate, 1-4 Family Investor, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 89,208 | $ 85,278
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0661 | 0.0675
Commercial Real Estate, Multifamily, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 78,108 | $ 84,526
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0579 | 0.0669
Commercial Real Estate |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 564,244 | $ 566,012
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.4182 | 0.4478
Commercial Advances to Mortgage Brokers Segment [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 18,541 | $ 0
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0137 | 0
Agricultural Mortgage, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 69,044 | $ 73,002
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0512 | 0.0577
Agricultural Other Portfolio Segment [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 30,950 | $ 31,983
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0229 | 0.0253
Agricultural [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 99,994 | $ 104,985
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0741 | 0.0830
Residential Real Estate, Senior Lien, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 313,459 | $ 300,225
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.2323 | 0.2375
Residential Real Estate, Junior Lien, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 5,945 | $ 3,282
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0044 | 0.0026
Residential Real Estate, Home Equity Lines of Credit, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 37,014 | $ 33,187
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0274 | 0.0263
Residential Mortgage |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 356,418 | $ 336,694
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.2641 | 0.2664
Consumer, Secured, Direct, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 37,948 | $ 37,127
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0281 | 0.0294
Consumer, Secured, Indirect, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 59,324 | $ 37,814
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0440 | 0.0298
Consumer, Unsecured, Portfolio Segment |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 3,256 | $ 3,113
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0024 | 0.0025
Total consumer [Member] |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Loans and Leases Receivable, Net of Deferred Income | $ 100,528 | $ 78,054
LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan | 0.0745 | 0.0617

X
- Definition LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan + References No definition available. + Details
Name: | isba_LoanPortfolioClassesAndSegmentsAsPercentageofAggregateLoan
Namespace Prefix: | isba_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

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_AccountsNotesAndLoansReceivableLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount before allowance and after 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481990/310-10-45-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-4 + Details
Name: | us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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

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

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

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

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=isba_CommercialRealEstate14FamilyInvestorPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

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

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

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

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