Loans Receivable And Allowance For Loan Losses: Financing Receivable Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	$ 925,866	$ 899,150
Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	129,373	132,661
Mortgage loans, multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	78,326	76,036
Mortgage loans, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	439,024	419,117
Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	75,026	75,411
Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	12,473	10,779
Mortgage loans, construction – commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	27,151	24,051
Mortgage loans, construction - Multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	17,024	19,256
Mortgage loans, construction - Land development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,064	1,803
Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	29,419	30,770
Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	39,103	40,190
Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	4,093	4,312
Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	73,790	64,764
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	906,528	877,552
Pass | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	126,562	129,748
Pass | Mortgage loans, multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	78,326	76,036
Pass | Mortgage loans, commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	427,832	405,165
Pass | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	73,984	75,178
Pass | Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	12,473	10,779
Pass | Mortgage loans, construction – commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	27,151	24,051
Pass | Mortgage loans, construction - Multi-family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	17,024	19,256
Pass | Mortgage loans, construction - Land development
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	926	1,659
Pass | Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	27,075	28,390
Pass | Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	38,303	39,364
Pass | Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	4,048	4,257
Pass | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	72,824	63,669
Watch
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	13,453	13,731
Watch | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,300	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	9,246	11,944
Watch | Mortgage loans, construction - custom and owner/builder
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,042	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	1,556	952
Watch | Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	41	41
Watch | Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	33	33
Watch | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	235	232
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	1,902	2,547
Special Mention | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	557	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	673	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	590	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	82	85
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	3,983	5,320
Substandard | Mortgage loans, one-to-four family
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	954	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	1,273	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	138	144
Substandard | Mortgage loans, land
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	198	211
Substandard | Consumer loans, home equity and second mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	759	785
Substandard | Consumer loans, other
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	12	22
Substandard | Commercial business loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans receivable	$ 649	$ 778