Income taxes - Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
Dec. 31, 2026 |
Dec. 31, 2025 |
|
| Income Tax Contingency [Line Items] | ||||||
| Estimated annual effective tax rate (as a percent) | 20.30% | (81.60%) | 37.90% | 171.00% | ||
| Unrecognized tax benefits that would impact effective tax rate | $ 46.3 | $ 46.3 | $ 46.0 | |||
| Unrecognized tax benefits, accrued interest and penalties | $ 0.0 | $ 0.0 | $ 0.0 | |||
| Estimated annual effective tax rate percent (as a percent) | 172.80% | |||||
| Forecast | ||||||
| Income Tax Contingency [Line Items] | ||||||
| Estimated annual effective tax rate (as a percent) | 41.60% | |||||