Retirement Benefit Plans - Total Accumulated Benefit Obligations and Plans with Accumulated Benefit Obligations in Excess of Plan Assets (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]
Total accumulated benefit obligations	$ 516.9	$ 472.0
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	516.9	472.0
Plan assets at fair market value	474.1	444.9
Foreign [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total accumulated benefit obligations	801.3	721.5
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	560.9	674.0
Plan assets at fair market value	$ 508.6	$ 612.9