Retirement Benefit Plan - Summary of Amounts Recognized in Balance Sheet (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]
Prepaid pension	$ 22.8	$ 24.0
Short-term accrued benefit liability	(5.6)	(0.4)
Long-term accrued benefit liability	(4.3)	(11.1)
Net amount recognized	12.9	12.5
Foreign-based Defined Benefit Plans [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Prepaid pension	14.9	10.2
Short-term accrued benefit liability	(0.8)	(0.7)
Long-term accrued benefit liability	(62.8)	(71.1)
Net amount recognized	$ (48.7)	$ (61.6)