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Fair Value (Quantitative information related to foreclosed assets) (Details) | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020
Discounted appraisal value [Member] | Level 3 [Member] | Loans Receivable, Collateralized By Cash Crop Inventory [Member] |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31) |  |
ImpairedFinancingReceivableFairValueDisclosureAppraisedValueDiscount | 40.00% | 40.00%

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- Definition Impaired Financing Receivable, Fair Value Disclosure, Appraised Value Discount + References No definition available. + Details
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Namespace Prefix: | isba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

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

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- Details
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Data Type: | na
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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
Data Type: | na
Balance Type: |
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