Retirement Benefit Plans - Total Accumulated Benefit Obligations and Plans with Accumulated Benefit Obligations in Excess of Plan Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
U.S. and Puerto Rico [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total accumulated benefit obligations	$ 412.1	$ 364.8
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	54.7	32.0
Plan assets at fair market value	45.2	21.8
Foreign-based Defined Benefit Plans [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Total accumulated benefit obligations	609.1	556.4
Plans with accumulated benefit obligations in excess of plan assets:
Accumulated benefit obligation	417.4	530.1
Plan assets at fair market value	$ 375.5	$ 475.3