Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2.6	$ 2.8
Interest cost	4.1	4.1
Expected return on plan assets	(2.9)	(2.9)
Net periodic benefit cost	3.8	4.0
Non U.S. Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	1.8	2.1
Interest cost	0.9	1.1
Expected return on plan assets	(0.3)	(0.4)
Net periodic benefit cost	$ 2.4	$ 2.8