Fair Value Measurement - Financial Assets and Liabilities by Hierarchy Level (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	$ 42.8	$ 51.2
Trading securities	18.5	14.3
Deferred compensation plan liabilities	(18.5)	(14.3)
Derivatives:
Forward exchange contracts-Assets	0.2	1.6
Forward exchange contracts-(Liabilities)	(0.2)	0.0
TOTAL	124.3	88.8
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0.0	0.0
Deferred compensation plan liabilities	(18.5)	(14.3)
Derivatives:
Forward exchange contracts-Assets	0.0	0.0
Forward exchange contracts-(Liabilities)	0.0	0.0
TOTAL	61.3	15.1
Quoted Prices in Active Markets for Similar Assets (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	42.8	48.9
Trading securities	0.0	0.0
Deferred compensation plan liabilities	0.0	0.0
Derivatives:
Forward exchange contracts-Assets	0.2	1.6
Forward exchange contracts-(Liabilities)	(0.2)	0.0
TOTAL	63.0	71.4
Unobservable inputs for which little or no market data exists (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0.0	2.3
Trading securities	0.0	0.0
Deferred compensation plan liabilities	0.0	0.0
Derivatives:
Forward exchange contracts-Assets	0.0	0.0
Forward exchange contracts-(Liabilities)	0.0	0.0
TOTAL	0.0	2.3
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	61.3	15.1
Money market funds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	61.3	15.1
Money market funds | Quoted Prices in Active Markets for Similar Assets (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0.0	0.0
Money market funds | Unobservable inputs for which little or no market data exists (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0.0	0.0
Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	20.2	20.9
Time Deposits | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0.0	0.0
Time Deposits | Quoted Prices in Active Markets for Similar Assets (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	20.2	20.9
Time Deposits | Unobservable inputs for which little or no market data exists (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 0.0	$ 0.0