XML 46 R36.htm IDEA: XBRL DOCUMENT
v3.25.3

Loans and ACL - Summary of Changes in ACL by Segments (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |
ACL, excluding accrued interest, beginning balance | $ 12,977 | $ 13,095 | $ 12,895 | $ 13,108
Charge-offs | (175) | (1,767) | (737) | (2,485)
Recoveries | 101 | 408 | 2,147 | 687
Provision for credit losses | (246) | 899 | (1,156) | 1,325
ACL, excluding accrued interest, beginning balance | 13,149 | 12,635 | 13,149 | 12,635
Commercial and Industrial |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |
ACL, excluding accrued interest, beginning balance | 1,318 | 1,264 | 1,316 | 968
Charge-offs | 0 | 0 | (72) | (336)
Recoveries | 6 | 6 | 90 | 10
Provision for credit losses | (29) | (46) | 19 | 582
ACL, excluding accrued interest, beginning balance | 1,353 | 1,224 | 1,353 | 1,224
Commercial Real Estate |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |
ACL, excluding accrued interest, beginning balance | 5,277 | 5,569 | 5,171 | 5,878
Charge-offs | 0 | 0 | 0 | 0
Recoveries | 4 | 318 | 56 | 353
Provision for credit losses | (102) | (710) | 156 | (1,054)
ACL, excluding accrued interest, beginning balance | 5,383 | 5,177 | 5,383 | 5,177
Agricultural |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |
ACL, excluding accrued interest, beginning balance | 316 | 258 | 287 | 270
Charge-offs | 0 | 0 | 0 | 0
Recoveries | 0 | 0 | 0 | 2
Provision for credit losses | (1) | 0 | 30 | (14)
ACL, excluding accrued interest, beginning balance | 317 | 258 | 317 | 258
Residential Real Estate |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |
ACL, excluding accrued interest, beginning balance | 4,673 | 4,351 | 4,521 | 4,336
Charge-offs | 0 | 0 | (1) | (10)
Recoveries | 16 | 20 | 46 | 112
Provision for credit losses | (107) | (40) | 230 | (107)
ACL, excluding accrued interest, beginning balance | 4,796 | 4,331 | 4,796 | 4,331
Consumer |  |  |  |
Allowance for Loan and Lease Losses [Roll Forward] |  |  |  |
ACL, excluding accrued interest, beginning balance | 1,393 | 1,653 | 1,600 | 1,656
Charge-offs | (175) | (1,767) | (664) | (2,139)
Recoveries | 75 | 64 | 1,955 | 210
Provision for credit losses | (7) | 1,695 | (1,591) | 1,918
ACL, excluding accrued interest, beginning balance | $ 1,300 | $ 1,645 | $ 1,300 | $ 1,645

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_AllowanceForLoanAndLeaseLossesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479344/326-20-45-1 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of increase in allowance for credit loss on financing receivable from recovery. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (e) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(4) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 11B -Subparagraph (c)(3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-11B Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 79 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479294/326-20-55-79 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-6 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of credit loss expense (reversal of expense) for financing receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 326 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479319/326-20-50-13 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 220 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 22 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147476148/220-40-50-22 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(11)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1 + Details
Name: | us-gaap_ProvisionForLoanLossesExpensed
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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_CommercialRealEstateMember
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=us-gaap_ResidentialMortgageMember
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: |