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Employee benefit plans - Narrative (Details) - USD ($) $ in Thousands |  | 3 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
Jul. 01, 2018 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |  |  |
Deferred compensation plan liability |  | $ 72,663 |  | $ 72,663 |  | $ 60,924
Cash surrender value of policies |  | 73,279 |  | 73,279 |  | $ 61,549
Change in fair value of plan assets |  | 4,089 | $ 3,252 | 8,551 | $ 7,461 |
Change in fair value of deferred compensation liabilities |  | $ 4,097 | $ 3,297 | $ 8,560 | $ 7,453 |
U.S. |  |  |  |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |  |  |
Vesting percentage of participants (in percentage) | 100.00% |  |  |  |  |
Employer discretionary vesting period | 2 years |  |  |  |  |
Earnings receivable minimum term | 2 years |  |  |  |  |
Earnings receivable lump sum or annual installment maximum terms | 15 years |  |  |  |  |
Deferred compensation arrangement with individual, maximum re-deferral contractual term | 10 years |  |  |  |  |
U.S. | One-Year Anniversary of Approval of Contribution |  |  |  |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |  |  |
Employer discretionary vesting percentage (in percentage) | 50.00% |  |  |  |  |
U.S. | Two-Year Anniversary of Approval of Contribution |  |  |  |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |  |  |
Employer discretionary vesting percentage (in percentage) | 50.00% |  |  |  |  |
Minimum | U.S. |  |  |  |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |  |  |
Individual qualifying base compensation (in percentage) | 1.00% |  |  |  |  |
Individual qualifying bonus compensation (in percentage) | 1.00% |  |  |  |  |
Maximum | U.S. |  |  |  |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |  |  |  |
Individual qualifying base compensation (in percentage) | 80.00% |  |  |  |  |
Individual qualifying bonus compensation (in percentage) | 100.00% |  |  |  |  |

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