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Pensions and Other Post-retirement Benefits - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]      
Estimated contributions by employer to pension plans $ 5.0    
Percentage increase in the costs of covered health care benefits assumed when measuring net periodic benefit expense 6.50%    
Percentage decrease in health care benefits for successive year 0.20%    
Ultimate health care cost trend rate when measuring net periodic benefit expense 4.40%    
Percentage increase in health care benefit cost 6.70%    
Estimated future percentage of health care benefits 4.40%    
Defined contribution pension plan expense $ 13.4 $ 12.6 $ 11.7
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Estimated benefit payments, year one 31.6    
Estimated benefit payments, year two 31.3    
Estimated benefit payments, year three 31.7    
Estimated benefit payments, year four 32.2    
Estimated benefit payments, year five 32.8    
Estimated benefit payments, five years thereafter 171.7    
Other Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Estimated benefit payments, year one 2.2    
Estimated benefit payments, year two 1.9    
Estimated benefit payments, year three 1.9    
Estimated benefit payments, year four 2.0    
Estimated benefit payments, year five 1.9    
Estimated benefit payments, five years thereafter $ 9.0