XML 86 R75.htm IDEA: XBRL DOCUMENT
v3.22.4

Borrowed Funds (Pledged financial instruments) (Details) - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | ---
Debt Disclosure [Abstract] |  |
Pledged to secure borrowed funds | $ 347,331 | $ 334,415
Total | 454,320 | 412,742
Short-term Debt [Line Items] |  |
Pledged Financial Instruments, Available for Sale Securities, without Single Maturity Date | 58,291 | 50,173
Securities Sold under Agreements to Repurchase, Fair Value of Collateral | 58,291 | 50,173
Deposit Liabilities, Collateral Issued, Financial Instruments | 48,698 | 28,154
State and Local Funds Purchased [Member] |  |
Short-term Debt [Line Items] |  |
Pledged Financial Instruments, Available for Sale Securities, without Single Maturity Date | 11,037 | 13,491
Mortgage Backed Securities, Other [Member] |  |
Short-term Debt [Line Items] |  |
Pledged Financial Instruments, Available for Sale Securities, without Single Maturity Date | 6,819 | 13,174
Collateralized Mortgage Obligations [Member] |  |
Short-term Debt [Line Items] |  |
Pledged Financial Instruments, Available for Sale Securities, without Single Maturity Date | 11,084 | 13,797
US Treasury Securities |  |
Short-term Debt [Line Items] |  |
Pledged Financial Instruments, Available for Sale Securities, without Single Maturity Date | $ 29,351 | $ 9,711

X
- Definition Pledged Financial Instruments, Available for Sale Securities, without Single Maturity Date + References No definition available. + Details
Name: | isba_PledgedFinancialInstrumentsAvailableforSaleSecuritieswithoutSingleMaturityDate
Namespace Prefix: | isba_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Pledged Financial Instruments, Not Separately Reported, Securities And Loans Receivable, For Federal Home Loan Bank Debt And Federal Reserve Bank Discount Window + References No definition available. + Details
Name: | isba_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesAndLoansReceivableForFederalHomeLoanBankDebtAndFederalReserveBankDiscountWindow
Namespace Prefix: | isba_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Pledged Financial Instruments, Not Separately Reported, Securities And Loans Receivable Pledged As Collateral + References No definition available. + Details
Name: | isba_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesAndLoansReceivablePledgedAsCollateral
Namespace Prefix: | isba_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Amount of securities, mortgage loans, or other financial instruments pledged as collateral for deposits. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 405 -Section 50 -Paragraph 1 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=116652737&loc=d3e64164-112818 + Details
Name: | us-gaap_DepositLiabilitiesCollateralIssuedFinancialInstruments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of securities pledged as collateral against securities sold under agreement to repurchase. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 12 -URI https://asc.fasb.org/extlink&oid=99393222&loc=SL20226013-175313 + Details
Name: | us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseFairValueOfCollateral
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_ShortTermDebtLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ShortTermDebtTypeAxis=isba_StateandLocalFundsPurchasedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortTermDebtTypeAxis=us-gaap_MortgageBackedSecuritiesOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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