Loans Receivable And Allowance For Loan Losses: Schedule of loans evaluated individually for impairment and collectively evaluated for impairment in the allowance for loan losses (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$ 123		$ 127
Allowance for Loan Losses, Collectively Evaluated for Impairment	15,184		13,576
Allowance for Loan Losses, Total	15,307	$ 14,698	13,703	$ 13,433	$ 13,433	$ 13,469
Recorded Investment in Loans, Individually Evaluated for Impairment	4,190		4,532
Recorded Investment in Loans, Collectively Evaluated for Impairment	1,276,721		1,145,918
Loans receivable	1,280,911		1,150,450
Mortgage loans, one-to-four family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	2,178		1,658
Allowance for Loan Losses, Total	2,178	2,052	1,658	1,356	1,247	1,154
Recorded Investment in Loans, Individually Evaluated for Impairment	373		388
Recorded Investment in Loans, Collectively Evaluated for Impairment	228,901		175,728
Loans receivable	229,274		176,116
Mortgage loans, multi-family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,012		855
Allowance for Loan Losses, Total	1,012	938	855	888	735	765
Recorded Investment in Loans, Individually Evaluated for Impairment	0		0
Recorded Investment in Loans, Collectively Evaluated for Impairment	111,777		95,025
Loans receivable	111,777		95,025
Mortgage loans, commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	7,029		6,682
Allowance for Loan Losses, Total	7,029	6,904	6,682	6,763	6,931	6,813
Recorded Investment in Loans, Individually Evaluated for Impairment	2,988		2,988
Recorded Investment in Loans, Collectively Evaluated for Impairment	554,027		533,662
Loans receivable	557,015		536,650
Mortgage loans, construction - custom and owner/builder
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	799		675
Allowance for Loan Losses, Total	799	726	675	733	686	644
Recorded Investment in Loans, Individually Evaluated for Impairment	0		0
Recorded Investment in Loans, Collectively Evaluated for Impairment	78,739		67,091
Loans receivable	78,739		67,091
Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	110		130
Allowance for Loan Losses, Total	110	121	130	93	126	188
Recorded Investment in Loans, Individually Evaluated for Impairment	0		0
Recorded Investment in Loans, Collectively Evaluated for Impairment	7,037		8,364
Loans receivable	7,037		8,364
Mortgage loans, construction – commercial
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	291		343
Allowance for Loan Losses, Total	291	267	343	354	463	784
Recorded Investment in Loans, Individually Evaluated for Impairment	0		0
Recorded Investment in Loans, Collectively Evaluated for Impairment	24,300		29,059
Loans receivable	24,300		29,059
Mortgage loans, construction - Multi-family
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	692		447
Allowance for Loan Losses, Total	692	662	447	328	436	436
Recorded Investment in Loans, Individually Evaluated for Impairment	0		0
Recorded Investment in Loans, Collectively Evaluated for Impairment	52,941		34,354
Loans receivable	52,941		34,354
Mortgage loans, construction - Land development
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	233		233
Allowance for Loan Losses, Total	233	245	233	239	126	124
Recorded Investment in Loans, Individually Evaluated for Impairment	0		0
Recorded Investment in Loans, Collectively Evaluated for Impairment	13,810		13,582
Loans receivable	13,810		13,582
Mortgage loans, land
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	389		397
Allowance for Loan Losses, Total	389	363	397	360	377	470
Recorded Investment in Loans, Individually Evaluated for Impairment	150		450
Recorded Investment in Loans, Collectively Evaluated for Impairment	25,758		26,404
Loans receivable	25,908		26,854
Consumer loans, home equity and second mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	542		440
Allowance for Loan Losses, Total	542	507	440	434	469	528
Recorded Investment in Loans, Individually Evaluated for Impairment	390		394
Recorded Investment in Loans, Collectively Evaluated for Impairment	39,618		34,793
Loans receivable	40,008		35,187
Consumer loans, other
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	51		42
Allowance for Loan Losses, Total	51	47	42	51	44	50
Recorded Investment in Loans, Individually Evaluated for Impairment	0		3
Recorded Investment in Loans, Collectively Evaluated for Impairment	2,469		2,125
Loans receivable	2,469		2,128
Commercial business loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	123		127
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,858		1,674
Allowance for Loan Losses, Total	1,981	$ 1,866	1,801	$ 1,834	$ 1,793	$ 1,513
Recorded Investment in Loans, Individually Evaluated for Impairment	289		309
Recorded Investment in Loans, Collectively Evaluated for Impairment	136,825		124,730
Loans receivable	137,114		125,039
SBA PPP Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	0		0
Allowance for Loan Losses, Total	0		0
Recorded Investment in Loans, Individually Evaluated for Impairment	0		0
Recorded Investment in Loans, Collectively Evaluated for Impairment	519		1,001
Loans receivable	$ 519		$ 1,001