Employee Benefit and Retirement Plans - Schedule of Company's Pension Cost And Supplemental Retirement Plans (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 0.1	$ 0.1	$ 0.1
Interest cost	$ 0.4	0.5	0.9	1.1
Amortization, net	(2.5)	(2.3)	(5.1)	(4.6)
Net periodic expense	(2.1)	(1.7)	(4.1)	(3.4)
United States [Member] | Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.2	0.7	0.4	1.4
Interest cost	11.5	12.3	23.1	24.7
Expected return on plan assets	(16.8)	(18.3)	(33.7)	(36.6)
Amortization, net	5.3	5.9	10.7	11.8
Net periodic expense	0.2	0.6	0.5	1.3
International [Member] | Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1.3	1.6	2.6	3.1
Interest cost	3.3	3.4	6.5	6.5
Expected return on plan assets	(3.9)	(4.7)	(7.9)	(9.1)
Amortization, net	0.6	0.6	1.3	1.2
Curtailment, settlement and termination (benefit) costs			0.3
Net periodic expense	$ 1.3	$ 0.9	$ 2.8	$ 1.7