Loans Receivable And Allowance For Loan Losses: Impaired Financing Receivables (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Recorded Investment
With no related allowance recorded	$ 5,395	$ 5,237
With an allowance recorded	569	700
Total:	5,964	5,937
Unpaid Principal Balance (Loan Balance Plus Charge Off)
With no related allowance recorded	5,678	5,446
With an allowance recorded	569	700
Total:	6,247	6,146
Related Allowance	105	172
Average Recorded Investment
With no related allowance recorded	5,317	4,731
With an allowance recorded	635	606
Total	5,952	5,337
Interest Income Recognized
With no related allowance recorded	58	331	[1]
With an allowance recorded	0	30
Total	58	361
Cash Basis Interest Income Recognized
With no related allowance recorded	36	287
With an allowance recorded	0	30
Total	36	317
Mortgage loans, one-to-four family
Recorded Investment
With no related allowance recorded	1,431	1,192
Total:	1,431	1,192
Unpaid Principal Balance (Loan Balance Plus Charge Off)
With no related allowance recorded	1,475	1,236
Total:	1,475	1,236
Related Allowance	0	0
Average Recorded Investment
With no related allowance recorded	1,312	1,110
Total	1,312	1,110
Interest Income Recognized
With no related allowance recorded	5	71	[1]
Total	5	71
Cash Basis Interest Income Recognized
With no related allowance recorded	5	62
Total	5	62
Mortgage loans, commercial
Recorded Investment
With no related allowance recorded	3,141	3,190
Total:	3,141	3,190
Unpaid Principal Balance (Loan Balance Plus Charge Off)
With no related allowance recorded	3,141	3,190
Total:	3,141	3,190
Related Allowance	0	0
Average Recorded Investment
With no related allowance recorded	3,166	2,920
Total	3,166	2,920
Interest Income Recognized
With no related allowance recorded	53	227	[1]
Total	53	227
Cash Basis Interest Income Recognized
With no related allowance recorded	31	192
Total	31	192
Mortgage loans, land
Recorded Investment
With no related allowance recorded	59	63
With an allowance recorded	139	141
Total:	198	204
Unpaid Principal Balance (Loan Balance Plus Charge Off)
With no related allowance recorded	181	126
With an allowance recorded	139	141
Total:	320	267
Related Allowance	28	27
Average Recorded Investment
With no related allowance recorded	61	100
With an allowance recorded	140	246
Total	201	346
Interest Income Recognized
With no related allowance recorded	0	3	[1]
With an allowance recorded	0	0
Total	0	3
Cash Basis Interest Income Recognized
With no related allowance recorded	0	3
With an allowance recorded	0	0
Total	0	3
Consumer loans, home equity and second mortgage
Recorded Investment
With no related allowance recorded	581	603
Total:	581	603
Unpaid Principal Balance (Loan Balance Plus Charge Off)
With no related allowance recorded	581	603
Total:	581	603
Related Allowance	0	0
Average Recorded Investment
With no related allowance recorded	592	459
Total	592	459
Interest Income Recognized
With no related allowance recorded	0	0	[1]
Total	0	0
Cash Basis Interest Income Recognized
With no related allowance recorded	0	0
Total	0	0
Consumer loans, other
Recorded Investment
With an allowance recorded	12	23
Total:	12	23
Unpaid Principal Balance (Loan Balance Plus Charge Off)
With an allowance recorded	12	23
Total:	12	23
Related Allowance	6	17
Average Recorded Investment
With an allowance recorded	18	10
Total	18	10
Interest Income Recognized
With an allowance recorded	0	0
Total	0	0
Cash Basis Interest Income Recognized
With an allowance recorded	0
Total	0	0
Commercial business loans
Recorded Investment
With no related allowance recorded	183	189
With an allowance recorded	418	536
Total:	601	725
Unpaid Principal Balance (Loan Balance Plus Charge Off)
With no related allowance recorded	300	291
With an allowance recorded	418	536
Total:	718	827
Related Allowance	71	128
Average Recorded Investment
With no related allowance recorded	186	142
With an allowance recorded	477	350
Total	663	492
Interest Income Recognized
With no related allowance recorded	0	30	[1]
With an allowance recorded	0	30
Total	0	60
Cash Basis Interest Income Recognized
With no related allowance recorded	0	30
With an allowance recorded	0	30
Total	$ 0	$ 60

[1] For the three months ended December 31, 2019