Commitments and Contingencies - Components of Lease Cost, Supplemental Cash Flow and Other Information Related to Leases (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Lease, Cost [Abstract]
Operating lease cost	$ 50.3	$ 49.7
Sublease income	(0.9)	(0.9)
Total lease cost	49.4	48.8
Operating cash flows from operating leases	36.3	35.5
Right-of-use assets obtained in exchange for lease obligations	$ 22.4	$ 14.0
Weighted-average remaining lease term of operating leases (years)	6 years	6 years 2 months 12 days
Weighted-average discount rate of operating leases	5.60%	5.70%