Accrual of interest on loans due discontinued period.

No definition available.

Name:	iroq_AccrualOfInterestOnLoansDueDiscontinuedPeriod
Namespace Prefix:	iroq_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Cash And Cash Equivalents Maximum Original Maturity Period

+ References

No definition available.

+ Details

Name:	iroq_CashAndCashEquivalentsMaximumOriginalMaturityPeriod
Namespace Prefix:	iroq_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Income Tax Examination Minimum Likelihood Of Tax Benefits Being Realized Upon Settlement.

+ References

No definition available.

+ Details

Name:	iroq_IncomeTaxExaminationMinimumLikelihoodOfTaxBenefitsBeingRealizedUponSettlement
Namespace Prefix:	iroq_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest bearing deposits maturity period.

+ References

No definition available.

+ Details

Name:	iroq_InterestBearingDepositsMaturityPeriod
Namespace Prefix:	iroq_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of full service banking offices.

+ References

No definition available.

+ Details

Name:	iroq_NumberOfFullServiceBankingOffices
Namespace Prefix:	iroq_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of major customer revenues.

+ References

No definition available.

+ Details

Name:	iroq_PercentageOfMajorCustomerRevenues
Namespace Prefix:	iroq_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of cash as of the balance sheet date that is not insured by the Federal Deposit Insurance Corporation.

+ References

No definition available.

+ Details

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

- 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

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

- Definition

Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

+ References

No definition available.

+ Details

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

- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482099/360-10-50-2

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482130/360-10-45-4

+ Details

Name:	us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481696/310-30-50-2

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (g)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480418/310-10-S99-4

+ Details

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of expected credit loss for credit exposure on off-balance-sheet commitment, including but not limited to, loan commitment, standby letter of credit, financial guarantee not accounted for as insurance. Excludes off-balance sheet credit exposure accounted for as insurance and instrument accounted for under derivatives and hedging.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482454/460-10-45-1

+ Details

Name:	us-gaap_OffBalanceSheetCreditLossLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of accumulated undistributed earnings (deficit).

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481372/852-10-55-10

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (g)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 2
-Subparagraph (h)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480016/944-40-65-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-11

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(a)(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(17))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480008/505-10-S99-1

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30)(a)(3))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_RetainedEarningsAccumulatedDeficit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_SalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Jun. 30, 2023 USD ($) Banking_Office	Jun. 30, 2022 USD ($)	Jul. 01, 2022 USD ($)	Jun. 30, 2021 USD ($)
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Number of full service banking offices \| Banking_Office	7
Interest-bearing deposits, maturity period (in months)	3 years
Liquid investments with original maturity period	3 months
Accrual of interest on loans due discontinued period, in days	90 days
Percentage of minimum likelihood of realized tax benefit upon settlement	50.00%
Cash, Uninsured Amount	$ 350,000
Federal home loan bank stock and federal reserve bank stock	5,080,000
Long-Lived Asset Impairment	0	$ 0
Retained earnings	43,365,000	40,362,000
Allowance for loan losses	7,139,000	7,052,000		$ 6,599,000
Allowance for credit losses on off-balance sheet credit exposure	$ 216,000	$ 0	$ 496,000,000
Accounting Standards Update 2016-13 [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Retained earnings			388,000
Allowance for loan losses			47,000
Allowance for credit losses on off-balance sheet credit exposure			$ 496,000
Sales [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Percentage of major customer revenues	10.00%