Investment Securities: Other than Temporary Impairment, Credit Losses Recognized in Earnings (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of year	$ 836	$ 853	$ 885
Additional increases to the amount related to credit losses for which OTTI was previously recognized	0	0	2
Net realized gain (losses) previously recorded as credit losses	(11)	1	(12)
Recovery of prior credit loss	(9)	(18)	(22)
Balance, end of year	$ 816	$ 836	$ 853

Other Than Temporary Impairment, Credit Losses Recognized In Earnings, Net Realized Gain (Loss)

No definition available.

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- Definition

This item represents an increase to the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held for which a previous OTTI was recognized and the investor does not intend to sell the debt security and it is not more likely than not that the investor will be required to sell the debt security before recovery of its amortized cost basis.

+ References

+ Details

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- Definition

The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-8B

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8B
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481800/320-10-50-8B

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security held due to increases in cash flows expected to be collected and recognized over the remaining life of the security.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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