Defined Contribution and Defined Benefit Retirement - Components of Net Periodic Defined Benefit Pension Benefit Cost (Credit) (Detail) - Defined Benefit Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S.
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 2.2	$ 2.5	$ 2.7
Expected return on plan assets	(3.4)	(3.3)	(3.4)
Amortization of unrecognized net actuarial loss	2.0	2.0	1.9
Total	0.8	1.2	1.2
Foreign
Defined Benefit Plan Disclosure [Line Items]
Service cost	11.6	11.4	9.9
Interest cost	13.8	13.4	15.1
Settlement loss		0.1
Expected return on plan assets	(12.7)	(9.7)	(14.9)
Amortization of unrecognized prior service credit	0.2	0.3	0.2
Amortization of unrecognized net actuarial loss	13.2	13.2	11.4
Total	$ 26.1	$ 28.7	$ 21.7