v3.26.1
Accumulated other comprehensive income (loss) - Summary Of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning Balance $ 236.2 $ 807.0 $ 228.1 $ 762.7
Ending Balance 219.1 890.8 219.1 890.8
Currency translation reserve        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning Balance (15.3) (40.4) (23.5) (51.7)
Other comprehensive income (loss), net of taxes 7.8 26.3 16.0 37.6
Reclass from AOCI, net of taxes 0.0 0.0 0.0 0.0
Ending Balance (7.5) (14.1) (7.5) (14.1)
Cash flow hedge reserve        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning Balance (0.9) (5.2) (0.6) (3.3)
Other comprehensive income (loss), net of taxes (7.9) (5.9) (7.2) (7.5)
Reclass from AOCI, net of taxes (1.3) 0.3 (2.3) 0.0
Ending Balance (10.1) (10.8) (10.1) (10.8)
Defined benefit plans reserve        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning Balance 2.1 (0.3) 3.5 (0.2)
Other comprehensive income (loss), net of taxes 0.4 0.7 (1.0) 0.6
Reclass from AOCI, net of taxes 0.0 0.0 0.0 0.0
Ending Balance 2.5 0.4 2.5 0.4
Total        
Accumulated Other Comprehensive Income (Loss) [Line Items]        
Beginning Balance (14.1) (45.9) (20.6) (55.2)
Other comprehensive income (loss), net of taxes 0.3 21.1 7.8 30.7
Reclass from AOCI, net of taxes (1.3) 0.3 (2.3) 0.0
Ending Balance $ (15.1) $ (24.5) $ (15.1) $ (24.5)