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Changes in Level 3 Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Beginning balance	$ 4,571	$ 2,769
Included in accumulated other comprehensive income	10	(8)
Included in earnings attributable to realized gains / losses	(59)	(68)
Transfers into level 3	0	250
Transfers out of level 3	0	0
Amortization of bond premium and discount, net	2	0
Purchases	74	1,424
Sales	(263)	(79)
Ending balance	4,335	4,288
Gains (losses) included in earnings attributable to the change in unrealized gains (losses) related to assets still held at end of reporting period	$ (59)	$ (5)

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Fair value measurement with unobservable inputs reconciliation recurring basis asset amortization of bond premium and discount, net.

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Amount of unrealized gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3) and still held.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
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Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

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Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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