Leases - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lessee Lease Description [Line Items]
Operating lease costs	$ 66.6	$ 72.3	$ 78.0
Cash paid for operating lease liabilities included in operating cashflows	69.3	74.3	79.4
Right-of-use assets obtained in exchange for operating lease liabilities	$ 22.6	$ 26.5
Weighted average remaining lease term	6 years 6 months	7 years
Weighted average discount rates	5.10%	4.90%
Real Estate Office Space [Member]
Lessee Lease Description [Line Items]
Total gross sublease and other rental income	$ 6.3	$ 6.0	9.1
Lease Agreements [Member]
Lessee Lease Description [Line Items]
Operating lease expense	$ 1.3	$ 1.3	$ 2.1