XML 59 R50.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Borrowed Funds (Short-term borrowings) (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Securities Sold under Agreements to Repurchase [Member] |  |  |  |
Short-term Debt [Line Items] |  |  |  |
Maximum Month End Balance | $ 54,051 | $ 67,519 | $ 54,051 | $ 67,519
Average Balance | $ 49,267 | $ 62,790 | $ 48,118 | $ 56,422
Weighted Average Interest Rate During the Period | 0.07% | 0.10% | 0.07% | 0.11%
Federal Funds Purchased [Member] |  |  |  |
Short-term Debt [Line Items] |  |  |  |
Maximum Month End Balance | $ 0 | $ 0 | $ 0 | $ 80
Average Balance | $ 0 | $ 0 | $ 1 | $ 2
Weighted Average Interest Rate During the Period | 0.00% | 0.52% | 0.79% | 0.40%

X
- Definition Short term debt weighted average interest rates. + References No definition available. + Details
Name: | isba_ShortTermDebtWeightedAverageInterestRates
Namespace Prefix: | isba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
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 No definition available. + Details
Name: | us-gaap_ShortTermDebtLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-K (SK) -Number 229 -Section 1402 -Paragraph (a) Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher SEC -Name Regulation S-K (SK) -Number 229 -Section 1402 -Paragraph (b) -Subparagraph (1) + Details
Name: | us-gaap_ShorttermDebtAverageOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period. + 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 https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_ShorttermDebtMaximumMonthendOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

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