v3.26.1
Share-based compensation plans - Compensation Expense (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based payment expense $ 7.4 $ 6.0
Cash based awards 0.3 0.3
Income tax benefit (1.7) (1.4)
Share-based payment expense, net of tax 5.7 4.6
Performance Shares Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based payment expense 4.0 3.0
Restricted Stock Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based payment expense 2.7 2.3
Deferred Stock Units    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based payment expense $ 0.4 $ 0.4