v3.25.4
Commitments and Contingencies (Detail)
$ in Millions
 12 Months Ended
Dec. 31, 2025
USD ($)
facility
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Contingencies And Commitments [Line Items]      
Environmental Remediation Expense Statement Of Income Or Comprehensive Income Extensible Enumeration Not Disclosed Flag pre-tax charges pre-tax charges pre-tax charges
Environmental Loss Contingency Statement Of Financial Position Extensible Enumeration Not Disclosed Flag environmental accruals environmental accruals  
Environmental Matters      
Contingencies And Commitments [Line Items]      
Pretax charge to comply U.S. federal, state and local environmental control and protection regulations $ 20.3 $ 22.7 $ 20.0
Capital expenditure to comply environmental regulations 1.2 0.8 $ 0.7
Environmental reserves 107.2 103.4  
Environmental reserves included in current liabilities $ 6.9 $ 9.2  
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration] Accrued liabilities – other Accrued liabilities – other  
Government Operations | Environmental Matters      
Contingencies And Commitments [Line Items]      
Number of facilities | facility 2    
Financial assurance to pay expected cost of decommissioning $ 71.5 $ 68.1  
Commercial Operations | Environmental Matters      
Contingencies And Commitments [Line Items]      
Financial assurance to pay expected cost of decommissioning $ 32.5 $ 28.5