Loans Receivable And Allowance For Loan Losses: Financing Receivable Credit Quality Indicators (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	$ 1,032,376	$ 899,150
Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	120,514	132,661
Mortgage loans, multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	79,468	76,036
Mortgage loans, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	455,454	419,117
Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	73,011	75,411
Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	7,412	10,779
Mortgage loans, construction – commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	19,793	24,051
Mortgage loans, construction - Multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	14,430	19,256
Mortgage loans, construction - Land development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	3,161	1,803
Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	27,009	30,770
Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	34,405	40,190
Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	3,552	4,312
Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	71,586	64,764
SBA PPP Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	122,581
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,015,005	877,552
Pass | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	117,647	129,748
Pass | Mortgage loans, multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	79,468	76,036
Pass | Mortgage loans, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	445,544	405,165
Pass | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	72,208	75,178
Pass | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	7,412	10,779
Pass | Mortgage loans, construction – commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	19,793	24,051
Pass | Mortgage loans, construction - Multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	14,430	19,256
Pass | Mortgage loans, construction - Land development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	3,035	1,659
Pass | Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	24,713	28,390
Pass | Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	33,867	39,364
Pass | Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	3,510	4,257
Pass | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	70,797	63,669
Pass | SBA PPP Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	122,581
Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	11,954	13,731
Watch | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,377	296
Watch | Mortgage loans, multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Watch | Mortgage loans, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	7,936	11,944
Watch | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	803	233
Watch | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Watch | Mortgage loans, construction – commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Watch | Mortgage loans, construction - Multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Watch | Mortgage loans, construction - Land development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Watch | Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,527	952
Watch | Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	54	41
Watch | Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	32	33
Watch | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	225	232
Watch | SBA PPP Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,785	2,547
Special Mention | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	553	562
Special Mention | Mortgage loans, multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Mortgage loans, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	572	683
Special Mention | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Mortgage loans, construction – commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Mortgage loans, construction - Multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Mortgage loans, construction - Land development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	584	1,217
Special Mention | Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Special Mention | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	76	85
Special Mention | SBA PPP Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	3,632	5,320
Substandard | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	937	2,055
Substandard | Mortgage loans, multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Substandard | Mortgage loans, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,402	1,325
Substandard | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Substandard | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Substandard | Mortgage loans, construction – commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Substandard | Mortgage loans, construction - Multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	0	0
Substandard | Mortgage loans, construction - Land development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	126	144
Substandard | Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	185	211
Substandard | Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	484	785
Substandard | Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	10	22
Substandard | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	488	$ 778
Substandard | SBA PPP Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	$ 0