Employee Benefit Plans - Components of Net Periodic Cost for Defined Benefit Pension Plan and Other Postretirement Benefit Plan (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Net periodic pension cost	$ 1.1	$ 4.8	$ 8.8
Defined Benefit Pension Plan [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	17.1	8.8	6.7
Actuarial loss (gain) amortization	8.2	13.6	17.3
Less: Expected return on plan assets	(22.3)	(15.9)	(13.1)
Net periodic pension cost	3.0	6.5	10.9
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	0.4	0.2	0.1
Actuarial loss (gain) amortization	(2.3)	(1.9)	(2.0)
Prior service credit amortization			(0.2)
Net periodic pension cost	$ (1.9)	$ (1.7)	$ (2.1)