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Acquisitions - Narrative (Details) £ / shares in Units, $ / shares in Units, $ in Thousands, £ in Millions |  | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Jan. 23, 2023 USD ($) employee | Jan. 23, 2023 GBP (£) employee | Mar. 31, 2024 USD ($) | Oct. 01, 2023 USD ($) program | Apr. 02, 2023 USD ($) | Sep. 29, 2024 USD ($) | Oct. 01, 2023 USD ($) program employee $ / shares | Oct. 02, 2022 USD ($) acquisition | Sep. 23, 2022 £ / shares
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Goodwill |  |  |  | $ 1,880,244 |  | $ 2,046,569 | $ 1,880,244 | $ 1,110,412 |
Acquisition and integration expenses |  |  |  |  |  | 7,138 | 33,169 | 0 |
(Loss) gain in contingent earn-out liabilities |  |  |  |  |  | $ (2,500) | (12,300) | (300) |
Minimum |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Earn-out period |  |  |  |  |  | 3 years |  |  |
Useful life of intangible assets |  |  |  |  |  | 1 year |  |  |
Significant unobservable input, earn-out period |  |  |  |  |  | 3 years |  |  |
Maximum |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Earn-out period |  |  |  |  |  | 5 years |  |  |
Useful life of intangible assets |  |  |  |  |  | 12 years |  |  |
Significant unobservable input, earn-out period |  |  |  |  |  | 5 years |  |  |
LS Technologies |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Fair value of acquisition purchase price |  |  | $ 120,000 |  |  |  |  |  |
Initial cash payments |  |  | 93,000 |  |  |  |  |  |
Cash holdback related to tax reserve |  |  | 4,000 |  |  |  |  |  |
Equity interests issued and issuable |  |  | 23,000 |  |  |  |  |  |
Net tangible assets |  |  | 12,000 |  |  |  |  |  |
Intangible assets |  |  | 23,000 |  |  |  |  |  |
Goodwill |  |  | 85,000 |  |  |  |  |  |
LS Technologies | Maximum |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Equity interests issued and issuable |  |  | $ 60,000 |  |  |  |  |  |
RPS Group PLC |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Fair value of acquisition purchase price | $ 784,000 | £ 633 |  |  |  |  |  |  |
Intangible assets | 174,094 |  |  |  |  |  |  |  |
Goodwill | $ 652,762 |  |  |  |  |  |  |  |
Price of acquisition, expected, per share (in pounds per share) | £ / shares |  |  |  |  |  |  |  |  | £ 2.22
Number of employees (over for Amyx) | employee | 5,000 | 5,000 |  |  |  |  |  |  |
Acquisition and integration expenses |  |  |  | $ 7,300 | $ 19,900 |  | 33,200 |  |
Net purchase price | $ 675,000 |  |  |  |  |  |  |  |
Revenue |  |  |  |  |  |  | 600,000 |  |
Net income (loss) |  |  |  |  |  |  | $ 3,600 |  |
Diluted earnings per share (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 0.01 |  |
Intangible amortization |  |  |  |  |  |  | $ 26,800 |  |
RPS Group PLC | Foreign Exchange Contract |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Foreign currency forward contract, asset fair value | $ 109,300 |  |  |  |  |  |  |  |
Amyx, Inc. |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Fair value of acquisition purchase price |  |  |  |  |  |  | $ 120,900 |  |
Number of employees (over for Amyx) | employee |  |  |  |  |  |  | 500 |  |
Number of government programs acquired (over) | program |  |  |  | 30 |  |  | 30 |  |
Promissory note |  |  |  |  |  |  | $ 100,000 |  |
Payables (receivables) related to estimated post-closing adjustments |  |  |  |  |  |  | 8,700 |  |
Contingent earn-out liability |  |  |  | $ 12,200 |  |  | 12,200 |  |
Aggregate maximum of contingent consideration |  |  |  | $ 25,000 |  |  | $ 25,000 |  |
Business acquisitions |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Fair value of acquisition purchase price |  |  |  |  |  |  |  | 88,300 |
Initial cash payments |  |  |  |  |  |  |  | 44,000 |
Promissory note |  |  |  |  |  |  |  | 15,500 |
Payables (receivables) related to estimated post-closing adjustments |  |  |  |  |  |  |  | (2,500) |
Contingent earn-out liability |  |  |  |  |  |  |  | 31,300 |
Aggregate maximum of contingent consideration |  |  |  |  |  |  |  | $ 47,000 |
Number of acquisitions | acquisition |  |  |  |  |  |  |  | 4 |
Business acquisitions | Minimum |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Earn-out period |  |  |  |  |  |  |  | 3 years |
Business acquisitions | Maximum |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |
Earn-out period |  |  |  |  |  |  |  | 5 years |

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