Fair Value Measurements: Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Fair value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments in equity securities	$ 811	$ 835
Recorded Amount
Fair value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	128,721	316,755
CDs held for investment	15,188	22,894
Investment securities	311,989	308,023
Investments in equity securities	811	835
FHLB stock	3,602	2,194
Other investments	3,000	3,000
Loans held for sale	400	748
Loans receivable, net	1,302,305	1,132,426
Accrued interest receivable	6,004	4,483
Certificates of deposit	300,100	122,584
Accrued interest payable	1,397	108
Fair Value
Fair value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	128,721	316,755
CDs held for investment	15,188	22,519
Investment securities	295,538	291,198
Investments in equity securities	811	835
FHLB stock	3,602	2,194
Other investments	3,000	3,000
Loans held for sale	407	758
Loans receivable, net	1,246,538	1,124,579
Accrued interest receivable	6,004	4,483
Certificates of deposit	297,542	120,807
Accrued interest payable	1,397	108
Fair Value \| Fair Value, Inputs, Level 1
Fair value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	128,721	316,755
CDs held for investment	15,188	22,519
Investment securities	161,538	158,578
Investments in equity securities	811	835
FHLB stock	3,602	2,194
Other investments	3,000	3,000
Loans held for sale	407	758
Loans receivable, net	0	0
Accrued interest receivable	6,004	4,483
Certificates of deposit	0	0
Accrued interest payable	1,397	108
Fair Value \| Fair Value, Inputs, Level 2
Fair value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
CDs held for investment	0	0
Investment securities	134,000	132,620
Investments in equity securities	0	0
FHLB stock	0	0
Other investments	0	0
Loans held for sale	0	0
Loans receivable, net	0	0
Accrued interest receivable	0	0
Certificates of deposit	0	0
Accrued interest payable	0	0
Fair Value \| Fair Value, Inputs, Level 3
Fair value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	0	0
CDs held for investment	0	0
Investment securities	0	0
Investments in equity securities	0	0
FHLB stock	0	0
Other investments	0	0
Loans held for sale	0	0
Loans receivable, net	1,246,538	1,124,579
Accrued interest receivable	0	0
Certificates of deposit	297,542	120,807
Accrued interest payable	$ 0	$ 0

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-Publisher FASB
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-Topic 210
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The fair value as of the balance sheet date of firm holdings in mortgages, mortgage backed securities (investment instruments that represent ownership of an undivided interest in a group of mortgages, where principal and interest from the individual mortgages are used to pay investors' principal and interest on the mortgage backed security) and asset-backed securities that are primarily paid from the cash flows of a discrete pool of receivables or other financial assets (such as credit-card receivables), either fixed or revolving, that by their terms convert into cash within a finite time period. Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
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-SubTopic 320
-Section 45
-Paragraph 2
-Publisher FASB
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- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
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-Subparagraph (a)
-Publisher FASB
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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-URI https://asc.fasb.org//310-10/tableOfContent

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- Definition

Amount of investments classified as other.

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-SubTopic 10
-Name Accounting Standards Codification
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