LOANS - Loan Portfolio by Credit Risk Rating (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Loans Portfolio by Credit Risk Rating [Abstract]
Total	$ 1,823,503	$ 1,623,531
Pass
Loans Portfolio by Credit Risk Rating [Abstract]
Total	1,797,596	1,590,893
Special Mention
Loans Portfolio by Credit Risk Rating [Abstract]
Total	12,064	11,545
Substandard
Loans Portfolio by Credit Risk Rating [Abstract]
Total	13,843	21,093
Doubtful
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Residential real estate
Loans Portfolio by Credit Risk Rating [Abstract]
Total	625,264	516,258
Residential real estate | Pass
Loans Portfolio by Credit Risk Rating [Abstract]
Total	618,809	512,595
Residential real estate | Special Mention
Loans Portfolio by Credit Risk Rating [Abstract]
Total	3,809	512
Residential real estate | Substandard
Loans Portfolio by Credit Risk Rating [Abstract]
Total	2,646	3,151
Residential real estate | Doubtful
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Multi-family
Loans Portfolio by Credit Risk Rating [Abstract]
Total	583,837	575,061
Multi-family | Pass
Loans Portfolio by Credit Risk Rating [Abstract]
Total	580,338	571,128
Multi-family | Special Mention
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Multi-family | Substandard
Loans Portfolio by Credit Risk Rating [Abstract]
Total	3,499	3,933
Multi-family | Doubtful
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Commercial Real Estate
Loans Portfolio by Credit Risk Rating [Abstract]
Total	533,460	472,984
Commercial Real Estate | Pass
Loans Portfolio by Credit Risk Rating [Abstract]
Total	519,268	453,321
Commercial Real Estate | Special Mention
Loans Portfolio by Credit Risk Rating [Abstract]
Total	7,177	8,085
Commercial Real Estate | Substandard
Loans Portfolio by Credit Risk Rating [Abstract]
Total	7,015	11,578
Commercial Real Estate | Doubtful
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Commercial and Industrial
Loans Portfolio by Credit Risk Rating [Abstract]
Total	67,918	46,285
Commercial and Industrial | Pass
Loans Portfolio by Credit Risk Rating [Abstract]
Total	66,157	43,314
Commercial and Industrial | Special Mention
Loans Portfolio by Credit Risk Rating [Abstract]
Total	1,078	540
Commercial and Industrial | Substandard
Loans Portfolio by Credit Risk Rating [Abstract]
Total	683	2,431
Commercial and Industrial | Doubtful
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Construction and land development
Loans Portfolio by Credit Risk Rating [Abstract]
Total	12,660	12,907
Construction and land development | Pass
Loans Portfolio by Credit Risk Rating [Abstract]
Total	12,660	10,499
Construction and land development | Special Mention
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	2,408
Construction and land development | Substandard
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Construction and land development | Doubtful
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Consumer
Loans Portfolio by Credit Risk Rating [Abstract]
Total	364	36
Consumer | Pass
Loans Portfolio by Credit Risk Rating [Abstract]
Total	364	36
Consumer | Special Mention
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Consumer | Substandard
Loans Portfolio by Credit Risk Rating [Abstract]
Total	0	0
Consumer | Doubtful
Loans Portfolio by Credit Risk Rating [Abstract]
Total	$ 0	$ 0