v3.26.1
Changes in Accumulated Other Comprehensive Loss (Classification Of Accumulated Other Comprehensive Income Reflected On Consolidated Balance Sheets) (Detail) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Balance, beginning of period $ 2,063.4  
Balance, end of period 2,099.2  
Deferred tax assets, other comprehensive loss 82.5 $ 83.3
Defined Benefit Pension and Postretirement Items    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Balance, beginning of period (213.8)  
Other comprehensive income before reclassifications 0.0  
Net period other comprehensive income 2.4  
Balance, end of period (211.4)  
Defined Benefit Pension and Postretirement Items | Reclassification out of Accumulated Other Comprehensive Income    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Amounts reclassified from accumulated other comprehensive loss 2.4  
Currency Translation Adjustment    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Balance, beginning of period 233.8  
Other comprehensive income before reclassifications (18.6)  
Net period other comprehensive income (18.6)  
Balance, end of period 215.2  
Currency Translation Adjustment | Reclassification out of Accumulated Other Comprehensive Income    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Amounts reclassified from accumulated other comprehensive loss 0.0  
Accumulated Other Comprehensive Loss    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Balance, beginning of period 20.0  
Other comprehensive income before reclassifications (18.6)  
Net period other comprehensive income (16.2)  
Balance, end of period 3.8  
Accumulated Other Comprehensive Loss | Reclassification out of Accumulated Other Comprehensive Income    
Increase (Decrease) in Stockholders' Equity [Roll Forward]    
Amounts reclassified from accumulated other comprehensive loss $ 2.4