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Repurchase of Shares - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2025 | May 07, 2025 | Aug. 02, 2023
Equity, Class of Treasury Stock [Line Items] |  |  |
Treasury Stock | 6,309 |  |
Average price at which ordinary shares are repurchased | $ 87.38 |  |
Share Repurchase Program August 2023 Member |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Share repurchase program, Authorized amount |  |  | $ 1,100.0
Share Repurchase Program May 2025 [Member] |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Share repurchase program, Authorized amount |  | $ 1,000.0 |
Remaining authority to repurchase outstanding ordinary shares | $ 986.4 |  |

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- Definition Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 505 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481520/505-30-50-4 + Details
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- Definition Amount remaining authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership. + References No definition available. + Details
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- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481549/505-30-45-1 + Details
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- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 10 -Topic 505 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
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