Pension, Post-Retirement and Post-Employment Plans - Changes in Funded Status of Pension and SERP Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in Fair Value of Plan Assets:
Beginning Balance	$ 261.6
Ending Balance	212.6	$ 261.6
Pension Plan and SERP | Domestic
Change in Projected Benefit Obligation:
Beginning of period balance	213.5	230.5
Additions	0.0	0.0
Service cost	0.0	0.0	$ 0.0
Plan amendments	0.0	0.0
Interest cost	8.8	10.1	6.8
Plan curtailment	0.0	0.0
Employee contributions	0.0	0.0
Actuarial (gain) loss due to assumption change	0.0	0.0
Actuarial loss (gain) due to plan experience	13.8	5.0
Benefits and expenses paid	(9.9)	(9.2)
Settlement	0.0	(22.9)
Foreign currency translation	0.0	0.0
End of period balance	226.2	213.5	230.5
Change in Fair Value of Plan Assets:
Beginning Balance	176.6	184.5
Additions	0.0	0.0
Actual return on plan assets, net of expenses	29.8	17.9
Employer contributions	3.1	6.2
Employee contributions	0.0	0.0
Benefits paid	(9.9)	(9.1)
Settlement	0.0	(22.9)
Foreign currency translation	0.0	0.0
Ending Balance	199.6	176.6	184.5
Funded status of plan	(26.6)	(36.9)
Pension Plan and SERP | Foreign
Change in Projected Benefit Obligation:
Beginning of period balance	103.0	112.7
Additions	0.6	2.7
Service cost	2.1	1.8	1.4
Plan amendments	0.0	(6.9)
Interest cost	2.3	3.1	2.8
Plan curtailment	(0.1)	(0.1)
Employee contributions	0.0	0.0
Actuarial (gain) loss due to assumption change	(1.4)	14.5
Actuarial loss (gain) due to plan experience	0.3	(2.1)
Benefits and expenses paid	(6.5)	(6.6)
Settlement	(72.2)	(2.5)
Foreign currency translation	6.1	(13.6)
End of period balance	34.2	103.0	112.7
Change in Fair Value of Plan Assets:
Beginning Balance	85.0	93.7
Additions	0.5	0.0
Actual return on plan assets, net of expenses	0.5	11.3
Employer contributions	1.8	2.5
Employee contributions	0.0	0.0
Benefits paid	(6.5)	(6.6)
Settlement	(72.2)	(2.5)
Foreign currency translation	3.9	(13.4)
Ending Balance	13.0	85.0	93.7
Funded status of plan	(21.2)	(18.0)
Post-retirement Medical Benefits | Domestic
Change in Projected Benefit Obligation:
Beginning of period balance	9.6	9.4
Additions	0.0	0.0
Service cost	0.0	0.1	0.1
Plan amendments	0.0	0.0
Interest cost	0.4	0.4	0.3
Plan curtailment	0.0	0.0
Employee contributions	0.0	0.3
Actuarial (gain) loss due to assumption change	0.0	0.0
Actuarial loss (gain) due to plan experience	0.2	0.2
Benefits and expenses paid	(0.5)	(0.8)
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
End of period balance	9.7	9.6	9.4
Change in Fair Value of Plan Assets:
Beginning Balance	0.0	0.0
Additions	0.0	0.0
Actual return on plan assets, net of expenses	0.0	0.0
Employer contributions	0.5	0.5
Employee contributions	0.0	0.3
Benefits paid	(0.5)	(0.8)
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
Ending Balance	0.0	0.0	0.0
Funded status of plan	(9.7)	(9.6)
Post-retirement Medical Benefits | Foreign
Change in Projected Benefit Obligation:
Beginning of period balance	3.1	1.4
Additions	0.0	0.0
Service cost	0.1	0.1	0.1
Plan amendments	0.0	0.0
Interest cost	0.4	0.2	0.1
Plan curtailment	0.0	0.0
Employee contributions	0.0	0.0
Actuarial (gain) loss due to assumption change	0.3	0.5
Actuarial loss (gain) due to plan experience	0.9	0.6
Benefits and expenses paid	(0.2)	(0.1)
Settlement	0.0	0.0
Foreign currency translation	(0.1)	0.4
End of period balance	4.5	3.1	1.4
Change in Fair Value of Plan Assets:
Beginning Balance	0.0	0.0
Additions	0.0	0.0
Actual return on plan assets, net of expenses	0.0	0.0
Employer contributions	0.2	0.1
Employee contributions	0.0	0.0
Benefits paid	(0.2)	(0.1)
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
Ending Balance	0.0	0.0	$ 0.0
Funded status of plan	$ (4.5)	$ (3.1)