Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Domestic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2.6	$ 2.8	$ 5.2	$ 5.6
Interest cost	4.1	4.1	8.2	8.2
Expected return on plan assets	(2.9)	(2.9)	(5.8)	(5.8)
Net periodic benefit cost	3.8	4.0	7.6	8.0
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1.8	2.1	3.6	4.2
Interest cost	0.9	1.1	1.8	2.2
Expected return on plan assets	(0.3)	(0.4)	(0.6)	(0.8)
Net periodic benefit cost	$ 2.4	$ 2.8	$ 4.8	$ 5.6