Post Employment Plans - Fair Value of Pension Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 189.1	$ 165.4
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.2	1.2
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	123.7	108.1
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	64.2	56.1	$ 49.9
Equities
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	42.8	24.6
Equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.1
Equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	42.8	24.5
Equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	44.2	33.8
Bonds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	1.2	1.1
Bonds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	43.0	32.7
Bonds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Insurance contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	64.2	56.1
Insurance contracts | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Insurance contracts | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Insurance contracts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	64.2	56.1
Absolute return fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	30.8	44.9
Absolute return fund | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Absolute return fund | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	30.8	44.9
Absolute return fund | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	7.1	6.0
Other | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	0.0	0.0
Other | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	7.1	6.0
Other | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of pension plan assets	$ 0.0	$ 0.0