Retirement Benefit Plans - Components of Net Periodic Pension Expense (Detail) - U.S. and Puerto Rico [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Expected Future Pension Benefit Payment [Line Items]
Service cost	$ 7.5	$ 7.5
Interest cost	5.5	4.7
Expected return on plan assets	(11.8)	(10.1)
Amortization of prior service cost	(2.5)	(2.6)
Amortization of unrecognized actuarial loss	6.1	5.6
Net periodic pension expense	$ 4.8	$ 5.1