Goodwill and Other Intangible Assets - Summary of Changes in the Company's Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Balance on beginning	$ 240,327	$ 244,574
Fiscal year business combinations	13,071	184
Goodwill included within assets held for sale		(4,431)
Balance on ending	$ 253,398	$ 240,327

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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For the asset that is reclassified back to held and used from held-for-sale, the amount of impairment charge that is recognized on the reclassification date.

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