XML 73 R62.htm IDEA: XBRL DOCUMENT
v3.22.4

Loans and ALLL (Summary of information pertaining to impaired loans) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Outstanding Balance | $ 2,924 | $ 6,411
Impaired loans without a valuation allowance, Outstanding Balance | 19,094 | 20,499
Impaired loans, Outstanding Balance | 22,018 | 26,910
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 3,185 | 6,683
Impaired loans without a valuation allowance, Unpaid Principal Balance | 19,410 | 20,815
Impaired loans, Unpaid Principal Balance | 22,595 | 27,498
Impaired loans, Valuation Allowance | 451 | 578
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 4,969 | 8,093
Impaired loans without a valuation allowance, Average Outstanding Balance | 17,697 | 22,289
Impaired loans, Average Outstanding Balance | 22,666 | 30,382
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 200 | 334
Impaired loans without a valuation allowance, Interest Income Recognized | 1,021 | 1,400
Impaired loans, Interest Income Recognized | 1,221 | 1,734
Total commercial [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans, Outstanding Balance | 8,342 | 9,267
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans, Unpaid Principal Balance | 8,659 | 9,584
Impaired loans, Valuation Allowance | 12 | 13
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans, Average Outstanding Balance | 8,053 | 11,853
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans, Interest Income Recognized | 470 | 638
Commercial real estate [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Outstanding Balance | 183 | 192
Impaired loans without a valuation allowance, Outstanding Balance | 5,366 | 5,829
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 184 | 193
Impaired loans without a valuation allowance, Unpaid Principal Balance | 5,682 | 6,145
Impaired loans, Valuation Allowance | 12 | 9
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 189 | 1,668
Impaired loans without a valuation allowance, Average Outstanding Balance | 5,514 | 6,313
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 12 | 69
Impaired loans without a valuation allowance, Interest Income Recognized | 338 | 398
Commercial other [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Outstanding Balance | 0 | 2,802
Impaired loans without a valuation allowance, Outstanding Balance | 2,793 | 444
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 0 | 2,802
Impaired loans without a valuation allowance, Unpaid Principal Balance | 2,793 | 444
Impaired loans, Valuation Allowance | 0 | 4
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 1,724 | 1,909
Impaired loans without a valuation allowance, Average Outstanding Balance | 626 | 1,963
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 62 | 103
Impaired loans without a valuation allowance, Interest Income Recognized | 58 | 68
Total agricultural [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans, Outstanding Balance | 10,935 | 14,189
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans, Unpaid Principal Balance | 10,935 | 14,189
Impaired loans, Valuation Allowance | 0 | 0
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans, Average Outstanding Balance | 11,552 | 14,730
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans, Interest Income Recognized | 625 | 945
Agricultural real estate [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Outstanding Balance |  | 0
Impaired loans without a valuation allowance, Outstanding Balance | 8,522 | 9,538
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance |  | 0
Impaired loans without a valuation allowance, Unpaid Principal Balance | 8,522 | 9,538
Impaired loans, Valuation Allowance |  | 0
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Average Outstanding Balance |  | 553
Impaired loans without a valuation allowance, Average Outstanding Balance | 8,568 | 9,739
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans with a valuation allowance, Interest Income Recognized |  | 11
Impaired loans without a valuation allowance, Interest Income Recognized | 468 | 699
Agricultural other [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Outstanding Balance |  | 0
Impaired loans without a valuation allowance, Outstanding Balance | 2,413 | 4,651
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance |  | 0
Impaired loans without a valuation allowance, Unpaid Principal Balance | 2,413 | 4,651
Impaired loans, Valuation Allowance |  | 0
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Average Outstanding Balance |  | 169
Impaired loans without a valuation allowance, Average Outstanding Balance | 2,984 | 4,269
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans with a valuation allowance, Interest Income Recognized |  | 0
Impaired loans without a valuation allowance, Interest Income Recognized | 157 | 235
Total residential real estate [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans, Outstanding Balance | 2,741 | 3,454
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans, Unpaid Principal Balance | 3,001 | 3,725
Impaired loans, Valuation Allowance | 439 | 565
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans, Average Outstanding Balance | 3,061 | 3,799
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans, Interest Income Recognized | 126 | 151
Residential real estate senior liens [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Outstanding Balance | 2,741 | 3,417
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans with a valuation allowance, Unpaid Principal Balance | 3,001 | 3,688
Impaired loans, Valuation Allowance | 439 | 565
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans with a valuation allowance, Average Outstanding Balance | 3,056 | 3,794
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans with a valuation allowance, Interest Income Recognized | 126 | 151
Residential real estate home equity lines of credit [Member] |  |
Impaired Financing Receivable, Recorded Investment [Abstract] |  |
Impaired loans without a valuation allowance, Outstanding Balance | 0 | 37
Impaired Financing Receivable, Unpaid Principal Balance [Abstract] |  |
Impaired loans without a valuation allowance, Unpaid Principal Balance | 0 | 37
Impaired Financing Receivable, Average Recorded Investment [Abstract] |  |
Impaired loans without a valuation allowance, Average Outstanding Balance | 5 | 5
Impaired Financing Receivable, Interest Income, Accrual Method [Abstract] |  |
Impaired loans without a valuation allowance, Interest Income Recognized | $ 0 | $ 0

X
- Definition Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Definition Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Amount of allowance for credit losses related to recorded investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(3) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableRelatedAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment in impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5258-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c)(2) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of investment in impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 14A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953550-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (a)(4) -URI https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524 + Details
Name: | us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
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_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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