Captive Insurance Collateral - Schedule of Maturities of Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Due within one year	$ 2,829
Due after one year through five years	63,833
Due after five years through ten years	0
Total	$ 66,662	$ 69,933

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
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-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27198-111563

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 320
-Section 50
-Paragraph 3A
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-URI https://asc.fasb.org/extlink&oid=126980459&loc=SL120269850-112803

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Balance Type:	debit
Period Type:	instant