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, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in Plan Assets:
Beginning of period balance	$ 211.9
End of period balance	228.8	$ 211.9
Pension and SERP Benefits | Domestic
Change in Projected Benefit Obligation:
Beginning of period balance	227.9	206.2
Additions	0.0	0.0
Service cost	0.0	0.0	$ 0.0
Plan amendments	0.0	0.0
Interest cost	7.2	8.7	8.1
Plan curtailment	0.0	0.0
Actuarial loss due to assumption change	19.0	25.6
Actuarial (gain) loss due to plan experience	(4.6)	(1.1)
Benefits and expenses paid	(11.1)	(11.5)
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
End of period balance	238.4	227.9	206.2
Change in Plan Assets:
Beginning of period balance	205.9	184.7
Actual return on plan assets, net of expenses	28.5	32.2
Employer contributions	0.9	0.5
Benefits paid	(11.1)	(11.5)
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
End of period balance	224.2	205.9	184.7
Funded Status
Funded status of plan	(14.2)	(22.0)
Supplemental Information:
Accumulated benefit obligation	228.1	217.1
Plans with Accumulated Benefit Obligation in excess of Plan Assets:
Accumulated benefit obligation	8.1	217.1
Fair value plan assets	0.0	205.9
Plans with Projected Benefit Obligation in excess of Plan Assets:
Projected benefit obligation	238.4	227.9
Fair value plan assets	224.2	205.9
Pension and SERP Benefits | Foreign
Change in Projected Benefit Obligation:
Beginning of period balance	26.6	23.3
Additions	0.0	2.7
Service cost	0.7	0.7	1.2
Plan amendments	0.0	0.0
Interest cost	0.3	0.3	0.3
Plan curtailment	(0.1)	(0.1)
Actuarial loss due to assumption change	0.3	1.1
Actuarial (gain) loss due to plan experience	(0.2)	1.0
Benefits and expenses paid	(0.7)	(0.6)
Settlement	(2.8)	(1.6)
Foreign currency translation	2.0	(0.2)
End of period balance	26.1	26.6	23.3
Change in Plan Assets:
Beginning of period balance	6.0	4.3
Actual return on plan assets, net of expenses	0.2	1.4
Employer contributions	1.5	2.4
Benefits paid	(0.7)	(0.6)
Settlement	(2.8)	(1.6)
Foreign currency translation	0.4	0.1
End of period balance	4.6	6.0	4.3
Funded Status
Funded status of plan	(21.5)	(20.6)
Supplemental Information:
Accumulated benefit obligation	23.5	23.3
Plans with Accumulated Benefit Obligation in excess of Plan Assets:
Accumulated benefit obligation	23.4	23.2
Fair value plan assets	4.3	5.8
Plans with Projected Benefit Obligation in excess of Plan Assets:
Projected benefit obligation	25.9	26.5
Fair value plan assets	4.3	5.8
Post-retirement Medical Benefits | Domestic
Change in Projected Benefit Obligation:
Beginning of period balance	9.2	9.0
Additions	0.0	0.0
Service cost	0.0	0.0	0.0
Plan amendments	0.0	0.0
Interest cost	0.3	0.4	0.4
Plan curtailment	0.0	0.0
Actuarial loss due to assumption change	0.0	1.0
Actuarial (gain) loss due to plan experience	(0.5)	(0.6)
Benefits and expenses paid	(0.5)	(0.6)
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
End of period balance	8.5	9.2	9.0
Change in Plan Assets:
Beginning of period balance	0.0	0.0
Actual return on plan assets, net of expenses	0.0	0.0
Employer contributions	0.5	0.5
Benefits paid	(0.5)	(0.5)
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
End of period balance	0.0	0.0	0.0
Funded Status
Funded status of plan	(8.5)	(9.2)
Supplemental Information:
Accumulated benefit obligation	8.5	9.2
Plans with Accumulated Benefit Obligation in excess of Plan Assets:
Accumulated benefit obligation	8.5	9.2
Fair value plan assets	0.0	0.0
Plans with Projected Benefit Obligation in excess of Plan Assets:
Projected benefit obligation	8.5	9.2
Fair value plan assets	0.0	0.0
Post-retirement Medical Benefits | Foreign
Change in Projected Benefit Obligation:
Beginning of period balance	0.1	1.3
Additions	0.0	0.0
Service cost	0.0	0.1	0.1
Plan amendments	0.0	(1.4)
Interest cost	0.0	0.1	0.1
Plan curtailment	0.0	0.0
Actuarial loss due to assumption change	0.0	0.1
Actuarial (gain) loss due to plan experience	0.0	(0.1)
Benefits and expenses paid	0.0	0.0
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
End of period balance	0.1	0.1	1.3
Change in Plan Assets:
Beginning of period balance	0.0	0.0
Actual return on plan assets, net of expenses	0.0	0.0
Employer contributions	0.0	0.0
Benefits paid	0.0	0.0
Settlement	0.0	0.0
Foreign currency translation	0.0	0.0
End of period balance	0.0	0.0	$ 0.0
Funded Status
Funded status of plan	(0.1)	(0.1)
Supplemental Information:
Accumulated benefit obligation	0.1	0.1
Plans with Accumulated Benefit Obligation in excess of Plan Assets:
Accumulated benefit obligation	0.1	0.1
Fair value plan assets	0.0	0.0
Plans with Projected Benefit Obligation in excess of Plan Assets:
Projected benefit obligation	0.1	0.1
Fair value plan assets	$ 0.0	$ 0.0