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, 2023	Dec. 31, 2022
Lease, Cost [Abstract]
Operating lease cost	$ 49.7	$ 46.8
Sublease income	(0.9)	(0.9)
Total lease cost	48.8	45.9
Operating cash flows from operating leases	35.5	47.3
Right-of-use assets obtained in exchange for lease obligations	$ 14.0	$ 19.3
Weighted-average remaining lease term of operating leases (years)	6 years 2 months 12 days	3 years 8 months 12 days
Weighted-average discount rate of operating leases	5.70%	4.40%