Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Financing Receivable, Recorded Investment [Line Items]
Construction	$ 2,398	$ 2,809
Land	1,304	1,186
Farm	2,062	1,735
Nonresidential real estate	29,211	27,138
Consumer and other, Loans on deposits	1,607	1,813
Consumer and other, Home equity	6,853	6,155
Consumer and other, Automobile	42	69
Consumer and other, Unsecured	400	552
Loans Receivable, Recorded Investment	260,031	244,988
Undisbursed portion of loans in process	(296)	(5,118)
Deferred loan origination costs, net	42	113
Allowance for loan losses	(1,533)	(1,515)	$ (1,568)
Loans receivable - net	258,244	238,468
Commercial and industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	2,540	1,847
One-to four-family [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Recorded Investment	197,936	186,125
Allowance for loan losses	(773)	(862)	(1,059)
Residential real estate, Multi-family [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans Receivable, Recorded Investment	15,678	15,559
Allowance for loan losses	$ (243)	$ (192)	$ (94)

Reflects the gross carrying amount of unpaid loans secured by borrowers automobiles.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the gross carrying amount of unpaid loans issued against deposits.

+ References

No definition available.

+ Details

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- Definition

Reflects the gross carrying amount of unsecured unpaid loans.

+ References

No definition available.

+ Details

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- Definition

Amount before allowance of loans issued to agricultural institutions. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

+ References

No definition available.

+ Details

Name:	kffb_LoansReceivableCommercialLand
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

It represents the loans receivable of commercial non mortgage during the period.

+ References

No definition available.

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- 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.

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- 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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount before allowance of loans issued to build, improve or remodel a residential home. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

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- Definition

Amount before allowance of revolving, open-end loan, extended under a line of credit and secured by the borrower's residential property. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

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- Definition

Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

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- Definition

Amount of undisbursed portion of the loan receivable balance (loans in process). Excludes loans and leases covered under loss sharing agreements.

+ References

No definition available.

+ Details

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- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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- Definition

Amount before allowance of commercial loans issued to businesses to acquire, develop, construct, improve, or refinance land or building. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans covered under loss sharing agreements.

+ References

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