XML 71 R62.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Fair Value (Recorded amount of assets and liabilities measured at fair value) (Details) - USD ($) $ in Thousands | Sep. 30, 2022 | Dec. 31, 2021
--- | --- | ---
AFS Securities |  |
AFS securities | $ 581,233 | $ 490,601
Fair value, total | 596,197 | 509,624
US Treasury Securities |  |
AFS Securities |  |
AFS securities | 206,791 | 209,703
Level 1 [Member] |  |
AFS Securities |  |
Fair value, total | $ 0 | $ 0
Percent of assets and liabilities measured at fair value | 0.00% | 0.00%
Level 2 [Member] |  |
AFS Securities |  |
Fair value, total | $ 581,233 | $ 490,601
Percent of assets and liabilities measured at fair value | 97.49% | 96.27%
Level 3 [Member] |  |
AFS Securities |  |
Fair value, total | $ 14,964 | $ 19,023
Percent of assets and liabilities measured at fair value | 2.51% | 3.73%
Recurring items [Member] |  |
AFS Securities |  |
AFS securities | $ 581,233 | $ 490,601
Recurring items [Member] | States and political subdivisions [Member] |  |
AFS Securities |  |
AFS securities | 114,000 | 121,205
Recurring items [Member] | Auction rate money market preferred [Member] |  |
AFS Securities |  |
AFS securities | 2,479 | 3,242
Recurring items [Member] | Mortgage-backed securities [Member] |  |
AFS Securities |  |
AFS securities | 41,042 | 56,148
Recurring items [Member] | Collateralized mortgage obligations [Member] |  |
AFS Securities |  |
AFS securities | 209,720 | 92,301
Recurring items [Member] | Corporate Debt Securities |  |
AFS Securities |  |
AFS securities | 7,201 | 8,002
Recurring items [Member] | US Treasury Securities |  |
AFS Securities |  |
AFS securities | 206,791 | 209,703
Recurring items [Member] | Level 1 [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 1 [Member] | States and political subdivisions [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 1 [Member] | Auction rate money market preferred [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 1 [Member] | Mortgage-backed securities [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 1 [Member] | Collateralized mortgage obligations [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 1 [Member] | Corporate Debt Securities |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 1 [Member] | US Treasury Securities |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 2 [Member] |  |
AFS Securities |  |
AFS securities | 581,233 | 490,601
Recurring items [Member] | Level 2 [Member] | States and political subdivisions [Member] |  |
AFS Securities |  |
AFS securities | 114,000 | 121,205
Recurring items [Member] | Level 2 [Member] | Auction rate money market preferred [Member] |  |
AFS Securities |  |
AFS securities | 2,479 | 3,242
Recurring items [Member] | Level 2 [Member] | Mortgage-backed securities [Member] |  |
AFS Securities |  |
AFS securities | 41,042 | 56,148
Recurring items [Member] | Level 2 [Member] | Collateralized mortgage obligations [Member] |  |
AFS Securities |  |
AFS securities | 209,720 | 92,301
Recurring items [Member] | Level 2 [Member] | Corporate Debt Securities |  |
AFS Securities |  |
AFS securities | 7,201 | 8,002
Recurring items [Member] | Level 2 [Member] | US Treasury Securities |  |
AFS Securities |  |
AFS securities | 206,791 | 209,703
Recurring items [Member] | Level 3 [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 3 [Member] | States and political subdivisions [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 3 [Member] | Auction rate money market preferred [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 3 [Member] | Mortgage-backed securities [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 3 [Member] | Collateralized mortgage obligations [Member] |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 3 [Member] | Corporate Debt Securities |  |
AFS Securities |  |
AFS securities | 0 | 0
Recurring items [Member] | Level 3 [Member] | US Treasury Securities |  |
AFS Securities |  |
AFS securities | 0 | 0
Nonrecurring items [Member] |  |
AFS Securities |  |
Impaired loans (net of the allowance for loan losses) | 14,724 | 18,812
Foreclosed Assets, Fair Value Disclosure | 240 | 211
Nonrecurring items [Member] | Level 1 [Member] |  |
AFS Securities |  |
Impaired loans (net of the allowance for loan losses) | 0 | 0
Foreclosed Assets, Fair Value Disclosure | 0 | 0
Nonrecurring items [Member] | Level 2 [Member] |  |
AFS Securities |  |
Impaired loans (net of the allowance for loan losses) | 0 | 0
Foreclosed Assets, Fair Value Disclosure | 0 | 0
Nonrecurring items [Member] | Level 3 [Member] |  |
AFS Securities |  |
Impaired loans (net of the allowance for loan losses) | 14,724 | 18,812
Foreclosed Assets, Fair Value Disclosure | $ 240 | $ 211

X
- Definition Foreclosed Assets, Fair Value Disclosure + References No definition available. + Details
Name: | isba_ForeclosedAssetsFairValueDisclosure
Namespace Prefix: | isba_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Impaired Financing Receivable, Fair Value Disclosure + References No definition available. + Details
Name: | isba_ImpairedFinancingReceivableFairValueDisclosure
Namespace Prefix: | isba_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percent of assets and liabilities measured at fair value. + References No definition available. + Details
Name: | isba_PercentageOfAssetsAndLiabilitiesMeasuredAtFairValue
Namespace Prefix: | isba_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_AuctionRateSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |