Leases - Summary of Other Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases Operating [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 46.3	$ 47.6
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 48.0	$ 55.9
Weighted-average remaining lease term - operating leases	6 years	7 years
Weighted-average discount rate - operating leases	1.90%	2.30%