Loans Receivable And Allowance For Loan Losses: Schedule 1 of Troubled debt restructured loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	$ 3,248	$ 3,269
Accruing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	2,894	2,903
Non-Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	354	366
Mortgage loans, one-to-four family
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	628	634
Mortgage loans, one-to-four family | Accruing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	489	493
Mortgage loans, one-to-four family | Non-Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	139	141
Mortgage loans, commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	2,405	2,410
Mortgage loans, commercial | Accruing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	2,405	2,410
Mortgage loans, commercial | Non-Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	0	0
Consumer loans, home equity and second mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	79	82
Consumer loans, home equity and second mortgage | Accruing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	0	0
Consumer loans, home equity and second mortgage | Non-Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	79	82
Commercial business loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	136	143
Commercial business loans | Accruing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	0	0
Commercial business loans | Non-Accrual
Financing Receivable, Troubled Debt Restructuring [Line Items]
Troubled debt restructured loan	$ 136	$ 143