Equity-based Compensation - Summary of Restricted Stock and Restricted Stock Units Activity (Detail) shares in Thousands	12 Months Ended
Sep. 30, 2025 $ / shares shares
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Number of Restricted Shares, Outstanding, Beginning Balance \| shares	2,175
Number of Restricted Shares, Granted \| shares	1,027
Number of Restricted Shares, Vested \| shares	(932)
Number of Restricted Shares, Forfeited \| shares	(211)
Number of Restricted Shares, Ending Balance \| shares	2,059
Restricted Shares, Weighted Average Grant Date Fair Value, Beginning Balance \| $ / shares	$ 79.61
Restricted Shares, Weighted Average Grant Date Fair Value, Granted \| $ / shares	82.33
Restricted Shares, Weighted Average Grant Date Fair Value, Vested \| $ / shares	78.74
Restricted Shares, Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	62.84
Restricted Shares, Weighted Average Grant Date Fair Value, Ending Balance \| $ / shares	$ 83.08
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Number of Restricted Shares, Outstanding, Beginning Balance \| shares	619
Number of Restricted Shares, Granted \| shares	293
Number of Restricted Shares, Vested \| shares	(231)
Number of Restricted Shares, Forfeited \| shares	(42)
Number of Restricted Shares, Ending Balance \| shares	639
Restricted Shares, Weighted Average Grant Date Fair Value, Beginning Balance \| $ / shares	$ 83.21
Restricted Shares, Weighted Average Grant Date Fair Value, Granted \| $ / shares	83.07
Restricted Shares, Weighted Average Grant Date Fair Value, Vested \| $ / shares	81.08
Restricted Shares, Weighted Average Grant Date Fair Value, Forfeited \| $ / shares	84.41
Restricted Shares, Weighted Average Grant Date Fair Value, Ending Balance \| $ / shares	$ 83.84

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (h)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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