Pension, Post-Retirement and Post-Employment Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net periodic benefit expense:
Net periodic cost (benefit)	$ 12.8	$ 4.1	$ (1.0)
Pension Plan and SERP | Domestic
Net periodic benefit expense:
Service cost	0.0	0.0	0.0
Interest cost on the projected benefit obligation	8.8	10.1	6.8
Expected return on plan assets	(10.1)	(11.6)	(9.9)
Amortization of prior service cost	0.0	0.0	0.0
Amortization of actuarial net loss	0.0	0.0	0.0
Plan curtailment	0.0	0.0	0.0
Plan settlement	0.0	1.7	0.0
Net periodic cost (benefit)	(1.3)	0.2	(3.1)
Pension Plan and SERP | Foreign
Net periodic benefit expense:
Service cost	2.1	1.8	1.4
Interest cost on the projected benefit obligation	2.3	3.1	2.8
Expected return on plan assets	(1.9)	(2.6)	(2.7)
Amortization of prior service cost	0.0	0.6	0.0
Amortization of actuarial net loss	0.1	0.2	0.0
Plan curtailment	0.3	(0.1)	0.0
Plan settlement	10.2	0.2	0.0
Net periodic cost (benefit)	13.1	3.2	1.5
Post-retirement Medical Benefits | Domestic
Net periodic benefit expense:
Service cost	0.0	0.1	0.1
Interest cost on the projected benefit obligation	0.4	0.4	0.3
Amortization of actuarial net loss	0.0	0.0	0.0
Net periodic cost (benefit)	0.4	0.4	0.4
Post-retirement Medical Benefits | Foreign
Net periodic benefit expense:
Service cost	0.1	0.1	0.1
Interest cost on the projected benefit obligation	0.4	0.2	0.1
Amortization of actuarial net loss	0.1	0.0	0.0
Net periodic cost (benefit)	$ 0.6	$ 0.3	$ 0.2