Benefit Plans - Amounts Recorded in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Non-current liabilities	$ (73.6)	$ (70.8)
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(6.5)	(5.9)
Non-current liabilities	(60.5)	(56.2)
Benefit obligations in excess of the fair value of plan assets	(67.0)	(62.1)
Other post-retirement plans
Defined Benefit Plan Disclosure [Line Items]
Current liabilities	(1.1)	(1.3)
Non-current liabilities	(6.5)	(7.7)
Benefit obligations in excess of the fair value of plan assets	$ (7.6)	$ (9.0)