Pensions and Other Post-retirement Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Percentage increase in the costs of covered health care benefits assumed when measuring net periodic benefit expense		6.70%
Percentage decrease in health care benefits for successive year	0.30%	0.20%
Ultimate health care cost trend rate when measuring net periodic benefit expense		4.40%
Percentage increase in health care benefit cost	7.80%
Estimated future percentage of health care benefits	4.50%
Defined contribution pension plan expense	$ 13.6	$ 13.4	$ 12.6
Minimum
Defined Benefit Plan Disclosure [Line Items]
Estimated contributions by employer to pension plans	6.0
Maximum
Defined Benefit Plan Disclosure [Line Items]
Estimated contributions by employer to pension plans	8.0
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Estimated benefit payments, year one	30.5
Estimated benefit payments, year two	30.4
Estimated benefit payments, year three	30.7
Estimated benefit payments, year four	31.3
Estimated benefit payments, year five	31.9
Estimated benefit payments, five years thereafter	167.7
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Estimated benefit payments, year one	2.1
Estimated benefit payments, year two	2.1
Estimated benefit payments, year three	2.3
Estimated benefit payments, year four	2.2
Estimated benefit payments, year five	2.2
Estimated benefit payments, five years thereafter	$ 10.2