Loans Receivable (Details) - Schedule of purchased loans - USD ($) $ in Thousands	Mar. 31, 2023	Jun. 30, 2022
Schedule Of Purchased Loans Abstract
One- to four-family residential real estate	$ 366	$ 400

A tax based on the assessed value of real estate by the local government. The tax is usually based on the value of property (including the land).

No definition available.

Name:	kffb_OneToFourfamilyResidentialRealEstate
Namespace Prefix:	kffb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant