Retirement Benefit Plan - Summary of Amounts Recognized in Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
U.S. and Puerto Rico [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Short-term accrued benefit liability	$ (0.1)	$ (0.2)
Long-term accrued benefit liability	(42.7)	(26.9)
Net amount recognized	(42.8)	(27.1)
Foreign [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Prepaid pension	20.4	17.6
Short-term accrued benefit liability	(1.3)	(1.1)
Long-term accrued benefit liability	(81.7)	(91.7)
Net amount recognized	$ (62.6)	$ (75.2)