Loans Receivable And Allowance For Loan Losses: Schedule of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	$ 9,882	$ 9,533	$ 9,690	$ 9,530
Provision for (Recapture of) Loan Losses	2,000	0	2,200	0
Charge- offs	(1)	(14)	(26)	(16)
Recoveries	9	222	26	227
Allowance for loan losses, Ending Allowance	11,890	9,741	11,890	9,741
Mortgage loans, one-to-four family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	1,065	1,159	1,167	1,086
Provision for (Recapture of) Loan Losses	83	(72)	(21)	1
Charge- offs	0	0	0	0
Recoveries	1	67	3	67
Allowance for loan losses, Ending Allowance	1,149	1,154	1,149	1,154
Mortgage loans, multi-family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	499	449	481	433
Provision for (Recapture of) Loan Losses	96	21	114	37
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	595	470	595	470
Mortgage loans, commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	4,410	4,239	4,154	4,248
Provision for (Recapture of) Loan Losses	1,351	(267)	1,603	(276)
Charge- offs	0	0	0	0
Recoveries	1	150	5	150
Allowance for loan losses, Ending Allowance	5,762	4,122	5,762	4,122
Mortgage loans, construction - custom and owner/builder
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	754	643	755	671
Provision for (Recapture of) Loan Losses	(57)	23	(63)	(5)
Charge- offs	0	0	0	0
Recoveries	0	0	5	0
Allowance for loan losses, Ending Allowance	697	666	697	666
Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	248	206	212	178
Provision for (Recapture of) Loan Losses	(44)	43	(8)	71
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	204	249	204	249
Mortgage loans, construction – commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	403	386	338	563
Provision for (Recapture of) Loan Losses	20	(2)	85	(179)
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	423	384	423	384
Mortgage loans, construction - Multi-family
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	333	209	375	135
Provision for (Recapture of) Loan Losses	61	63	19	137
Charge- offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	394	272	394	272
Mortgage loans, construction - Land development
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	48	143	67	49
Provision for (Recapture of) Loan Losses	32	101	13	195
Charge- offs	0		0	0
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	80	244	80	244
Mortgage loans, land
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	654	757	697	844
Provision for (Recapture of) Loan Losses	19	(112)	(29)	(203)
Charge- offs	0	0	0	0
Recoveries	5	4	10	8
Allowance for loan losses, Ending Allowance	678	649	678	649
Consumer loans, home equity and second mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	609	666	623	649
Provision for (Recapture of) Loan Losses	47	5	33	22
Charge- offs	0	(4)	0	(4)
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	656	667	656	667
Consumer loans, other
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	87	101	99	117
Provision for (Recapture of) Loan Losses	(10)	11	(13)	(4)
Charge- offs	(1)	(1)	(11)	(3)
Recoveries	2	1	3	2
Allowance for loan losses, Ending Allowance	78	112	78	112
Commercial business loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, Beginning Allowance	772	575	722	557
Provision for (Recapture of) Loan Losses	402	186	467	204
Charge- offs	0	(9)	(15)	(9)
Recoveries	0	0	0	0
Allowance for loan losses, Ending Allowance	$ 1,174	$ 752	$ 1,174	$ 752

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Amount of recovery of financing receivables doubtful of collection that were previously charged off.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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