PA Consulting Redeemable Noncontrolling Interests - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Dec. 27, 2024	Dec. 29, 2023	Sep. 27, 2024
Business Acquisition [Line Items]
Repurchase of redeemable noncontrolling interests	$ 3,729	$ 24,360
Preference share effect on basic earnings per share (in dollars per share)	$ 0.04	$ 0.01
PA Consulting Group Limited
Business Acquisition [Line Items]
Allocated share-based compensation expense	$ 5,900	$ 1,600
Cash in employee benefit trust	$ 800		$ 2,100
PA Consulting Employees
Business Acquisition [Line Items]
Ownership interest of employees	70.00%		70.00%

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Employee Benefit Trust, Cash

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Section 50
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-Publisher FASB
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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.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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-Subparagraph (a)
-Publisher FASB
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- Definition

The cash outflow during the period for redemption of redeemable noncontrolling interests.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
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