v3.26.1
Share-based compensation plans - Compensation Expense (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based payment expense $ 8.3 $ 8.6 $ 15.7 $ 14.6
Cash based awards 0.4 0.5 0.7 0.8
Income tax benefit (1.9) (1.9) (3.6) (3.3)
Share-based payment expense, net of tax 6.4 6.7 12.1 11.3
Performance Shares Units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based payment expense 4.6 4.7 8.6 7.7
Restricted Stock Units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based payment expense 2.9 3.1 5.6 5.4
Deferred Stock Units        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based payment expense $ 0.4 $ 0.3 $ 0.8 $ 0.7