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Goodwill - Narrative (Details) - USD ($) $ in Thousands |  |  | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Aug. 19, 2024 | Jan. 09, 2024 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 31, 2023 | Dec. 31, 2022
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Purchase of subsidiary undertakings (net of cash acquired) |  |  | $ 85,629 | $ 5,100 |  |
Goodwill |  |  | 9,085,447 |  | $ 9,022,075 | $ 8,971,670
Goodwill, impairment loss |  |  | 0 |  | $ 0 |
HumanFirst Inc |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Business combination, consideration transferred |  | $ 13,300 |  |  |  |
Payments to acquire businesses, net of cash acquired |  | 7,800 |  |  |  |
Purchase of subsidiary undertakings (net of cash acquired) |  | 11,800 |  |  |  |
Cash acquired from acquisition |  | 4,000 |  |  |  |
Deferred consideration |  |  | 1,500 |  |  |
Goodwill |  | 2,700 |  |  |  |
Intangible assets acquired |  | $ 9,900 |  |  |  |
KCR S.A Group |  |  |  |  |  |
Acquired Finite-Lived Intangible Assets [Line Items] |  |  |  |  |  |
Business combination, consideration transferred | $ 95,100 |  |  |  |  |
Payments to acquire businesses, net of cash acquired | 77,800 |  |  |  |  |
Purchase of subsidiary undertakings (net of cash acquired) | 89,700 |  |  |  |  |
Cash acquired from acquisition | 11,900 |  |  |  |  |
Deferred consideration |  |  | $ 1,100 |  |  |
Goodwill | 50,300 |  |  |  |  |
Intangible assets acquired | 30,800 |  |  |  |  |
Fair value of contingent consideration | $ 4,300 |  |  |  |  |

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