XML 74 R64.htm IDEA: XBRL DOCUMENT v3.24.1.u1

Fair Value (Recorded amount of assets and liabilities measured at fair value) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
AFS Securities
AFS securities	$ 517,585	$ 528,148
Fair value, total	518,753	529,231
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	$ 517,585	$ 528,148
Percent of assets and liabilities measured at fair value	99.77%	99.80%
Level 3 [Member]
AFS Securities
Fair value, total	$ 1,168	$ 1,083
Percent of assets and liabilities measured at fair value	0.23%	0.20%
Recurring items [Member]
AFS Securities
AFS securities	$ 517,585	$ 528,148
Recurring items [Member] | US Treasury Securities
AFS Securities
AFS securities	214,226	214,801
Recurring items [Member] | States and political subdivisions [Member]
AFS Securities
AFS securities	90,470	92,876
Recurring items [Member] | Auction rate money market preferred [Member]
AFS Securities
AFS securities	3,013	2,931
Recurring items [Member] | Mortgage-backed securities [Member]
AFS Securities
AFS securities	31,044	32,815
Recurring items [Member] | Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	171,831	177,775
Recurring items [Member] | Corporate Debt Securities
AFS Securities
AFS securities	7,001	6,950
Recurring items [Member] | Level 1 [Member]
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 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 2 [Member]
AFS Securities
AFS securities	517,585	528,148
Recurring items [Member] | Level 2 [Member] | US Treasury Securities
AFS Securities
AFS securities	214,226	214,801
Recurring items [Member] | Level 2 [Member] | States and political subdivisions [Member]
AFS Securities
AFS securities	90,470	92,876
Recurring items [Member] | Level 2 [Member] | Auction rate money market preferred [Member]
AFS Securities
AFS securities	3,013	2,931
Recurring items [Member] | Level 2 [Member] | Mortgage-backed securities [Member]
AFS Securities
AFS securities	31,044	32,815
Recurring items [Member] | Level 2 [Member] | Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	171,831	177,775
Recurring items [Member] | Level 2 [Member] | Corporate Debt Securities
AFS Securities
AFS securities	7,001	6,950
Recurring items [Member] | Level 3 [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] | Level 3 [Member] | US Treasury Securities
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
Nonrecurring items [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	1,168	1,083
Nonrecurring items [Member] | Level 1 [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	0	0
Nonrecurring items [Member] | Level 2 [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	0	0
Nonrecurring items [Member] | Level 3 [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	$ 1,168	$ 1,083

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-types1: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
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

+ 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
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aa)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481830/320-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479130/326-30-45-1

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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_USTreasurySecuritiesMember
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_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: