Income taxes - Additional Information (Details) - USD ($) $ in Thousands |
6 Months Ended | ||
|---|---|---|---|
Jul. 18, 2025 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Income Tax Disclosure [Line Items] | |||
| Dividends received from Kronos Worldwide, Inc. | $ 3,522 | $ 13,384 | |
| Foreign country | Subsequent Event | |||
| Income Tax Disclosure [Line Items] | |||
| Percentage of before current income tax expense (benefit) | 15.00% | ||
| Percentage of reduction in enacted tax rate | 1.00% | ||
| Percentage of after current income tax expense (benefit) | 10.00% | ||
| Foreign country | Subsequent Event | Minimum | |||
| Income Tax Disclosure [Line Items] | |||
| Non-cash deferred income tax expense | $ 20,000 | ||
| Foreign country | Subsequent Event | Maximum | |||
| Income Tax Disclosure [Line Items] | |||
| Non-cash deferred income tax expense | $ 23,000 | ||
| Kronos | |||
| Income Tax Disclosure [Line Items] | |||
| Dividends received from Kronos Worldwide, Inc. | $ 3,500 | $ 13,400 | |