Benefit Plans - Amounts Recorded in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Non-current liabilities	$ (61.6)	$ (73.6)
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(6.2)	(6.5)
Non-current liabilities	(49.7)	(60.5)
Benefit obligations in excess of the fair value of plan assets	(55.9)	(67.0)
Other post-retirement plans
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(1.0)	(1.1)
Non-current liabilities	(5.6)	(6.5)
Benefit obligations in excess of the fair value of plan assets	$ (6.6)	$ (7.6)