Stock-based compensation - other information about stock options (Details) - USD ($) $ / shares in Units, $ in Millions |
12 Months Ended | ||
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Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
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| Weighted-average information about options granted | |||
| Grant date fair value per option (in dollars per share) | $ 6.05 | $ 9.86 | $ 9.64 |
| Expected stock price volatility | 32.00% | 34.00% | 33.00% |
| Risk free interest rate | 4.20% | 4.30% | 4.10% |
| Expected life of options | 6 years | 6 years | 6 years 2 months 12 days |
| Other information about stock options | |||
| Fair value of options vested | $ 12.5 | $ 13.7 | $ 14.2 |
| Intrinsic value of options exercised | $ 0.8 | $ 11.7 | $ 7.1 |
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- References No definition available.
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- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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