Fair Value Measurements (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Recurring fair value measurements [Member]
Assets, fair value measurements [Abstract]
Investments, Fair Value Disclosure	$ 15.9	$ 14.3
Interest rate swaps	4.1	5.7
Foreign Currency Contract, Asset, Fair Value Disclosure	1.0	2.1
Total Assets, Fair Value Disclosure	21.0	22.1
Liabilities, fair value measurements [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0.8	0.1
Deferred Compensation Liability, Current and Noncurrent	20.1	19.1
Total Liabilities, Fair Value Disclosure	20.9	19.2
Total debt	1,412.9	1,403.2
Total financial instruments not carried at fair value	1,412.9	1,403.2
Recurring fair value measurements [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets, fair value measurements [Abstract]
Investments, Fair Value Disclosure	0.0	0.0
Interest rate swaps	0.0	0.0
Foreign Currency Contract, Asset, Fair Value Disclosure	0.0	0.0
Total Assets, Fair Value Disclosure	0.0	0.0
Liabilities, fair value measurements [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0.0	0.0
Deferred Compensation Liability, Current and Noncurrent	0.0	0.0
Total Liabilities, Fair Value Disclosure	0.0	0.0
Total debt	0.0	0.0
Total financial instruments not carried at fair value	0.0	0.0
Recurring fair value measurements [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets, fair value measurements [Abstract]
Investments, Fair Value Disclosure	15.9	14.3
Interest rate swaps	4.1	5.7
Foreign Currency Contract, Asset, Fair Value Disclosure	1.0	2.1
Total Assets, Fair Value Disclosure	21.0	22.1
Liabilities, fair value measurements [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0.8	0.1
Deferred Compensation Liability, Current and Noncurrent	20.1	19.1
Total Liabilities, Fair Value Disclosure	20.9	19.2
Total debt	1,412.9	1,403.2
Total financial instruments not carried at fair value	1,412.9	1,403.2
Recurring fair value measurements [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets, fair value measurements [Abstract]
Investments, Fair Value Disclosure	0.0	0.0
Interest rate swaps	0.0	0.0
Foreign Currency Contract, Asset, Fair Value Disclosure	0.0	0.0
Total Assets, Fair Value Disclosure	0.0	0.0
Liabilities, fair value measurements [Abstract]
Foreign Currency Contracts, Liability, Fair Value Disclosure	0.0	0.0
Deferred Compensation Liability, Current and Noncurrent	0.0	0.0
Total Liabilities, Fair Value Disclosure	0.0	0.0
Total debt	0.0	0.0
Total financial instruments not carried at fair value	0.0	0.0
Designated as Hedging Instrument
Assets, fair value measurements [Abstract]
Interest rate swaps	4.1	$ 5.7
Designated as Hedging Instrument | Interest Rate Swap
Derivative, Notional Amount	$ 250.0