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, 2021	Dec. 31, 2020
Lease, Cost [Abstract]
Operating lease cost	$ 37.2	$ 32.5
Sublease income	(1.0)	(1.0)
Total lease cost	36.2	31.5
Operating cash flows from operating leases	41.5	28.5
Right-of-use assets obtained in exchange for lease obligations	$ 12.2	$ 13.6
Weighted-average remaining lease term of operating leases (years)	4 years 1 month 6 days	4 years 8 months 12 days
Weighted-average discount rate of operating leases	5.10%	5.50%