Loans Receivable and Allowance for Loan Losses: Schedule of Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	$ 9,826	$ 9,924	$ 10,427
Provision for (Recapture of) Loan Losses	(1,250)	0	(1,525)
Charge-offs	(133)	(368)	(424)
Recoveries	1,110	270	1,446
Allowance for loan losses, Ending Allowance	9,553	9,826	9,924
Mortgage loans, one-to-four family
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	1,239	1,480	1,650
Provision for (Recapture of) Loan Losses	(178)	(225)	(214)
Charge-offs	0	(72)	(220)
Recoveries	21	56	264
Allowance for loan losses, Ending Allowance	1,082	1,239	1,480
Mortgage loans, multi-family
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	473	392	387
Provision for (Recapture of) Loan Losses	(26)	81	2
Charge-offs	0	0	0
Recoveries	0	0	3
Allowance for loan losses, Ending Allowance	447	473	392
Mortgage loans, commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	4,384	4,065	4,836
Provision for (Recapture of) Loan Losses	(1,248)	528	(775)
Charge-offs	(13)	(209)	0
Recoveries	1,061	0	4
Allowance for loan losses, Ending Allowance	4,184	4,384	4,065
Mortgage loans, construction - custom and owner/builder
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	619	451	450
Provision for (Recapture of) Loan Losses	80	168	1
Charge-offs	0	0	0
Recoveries	0	0	0
Allowance for loan losses, Ending Allowance	699	619	451
Mortgage loans, construction - speculative one-to-four family
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	130	123	52
Provision for (Recapture of) Loan Losses	(8)	5	69
Charge-offs	0	0	0
Recoveries	6	2	2
Allowance for loan losses, Ending Allowance	128	130	123
Mortgage loans, construction - commercial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	268	426	78
Provision for (Recapture of) Loan Losses	35	(158)	348
Charge-offs	0	0	0
Recoveries	0	0	0
Allowance for loan losses, Ending Allowance	303	268	426
Mortgage loans, construction - multi-family
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	316	283	25
Provision for (Recapture of) Loan Losses	(143)	(148)	(867)
Charge-offs	0	0	0
Recoveries	0	181	1,125
Allowance for loan losses, Ending Allowance	173	316	283
Mortgage loans, land
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	820	1,021	1,434
Provision for (Recapture of) Loan Losses	189	(164)	(305)
Charge-offs	(110)	(61)	(145)
Recoveries	19	24	37
Allowance for loan losses, Ending Allowance	918	820	1,021
Consumer loans, home equity and second mortgage
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	939	1,073	879
Provision for (Recapture of) Loan Losses	44	(116)	242
Charge-offs	0	(18)	(50)
Recoveries	0	0	2
Allowance for loan losses, Ending Allowance	983	939	1,073
Consumer loans, other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	156	187	176
Provision for (Recapture of) Loan Losses	(28)	(25)	16
Charge-offs	(10)	(8)	(9)
Recoveries	3	2	4
Allowance for loan losses, Ending Allowance	121	156	187
Commercial business loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Allowance for loan losses, Beginning Allowance	482	423	460
Provision for (Recapture of) Loan Losses	33	54	(42)
Charge-offs	0	0	0
Recoveries	0	5	5
Allowance for loan losses, Ending Allowance	$ 515	$ 482	$ 423

A valuation allowance for financing receivables that are expected to be uncollectible.

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- Definition

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

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of direct write-downs of financing receivables charged against the allowance.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.11)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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