v3.26.1
Retirement Plans and Postretirement Benefits - Narrative (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Plan Assets, Contributions by Employer $ 0.5      
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year 2.9   $ 2.9  
Pension Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 0.6 $ 0.8 1.3 $ 1.5
Interest cost 2.8 3.0 5.6 5.9
Expected return on plan assets (3.0) (3.3) (6.0) (6.7)
Defined Benefit Plan, Amortization of Gain (Loss) 0.9 0.2 1.8 0.4
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) 1.3 0.6 2.7 1.2
Other Postretirement Benefits Plan [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Defined Benefit Plan, Service Cost 0.0 0.0 0.1 0.1
Interest cost 0.6 0.6 1.1 1.2
Defined Benefit Plan, Amortization of Gain (Loss) (0.1) (0.1) (0.3) (0.3)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) 0.5 0.5 0.9 1.0
Other Postretirement Benefits Plan [Member] | Cost of Sales [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax 0.6 0.7 1.2 1.3
Other Postretirement Benefits Plan [Member] | Selling, general, and administrative expenses [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax $ 0.1 $ 0.1 $ 0.2 $ 0.3