Fair Value Measurement - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($) contract	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	$ 55.5		$ 52.0
Trading securities	10.0		9.7
Purchase of trading securities related to deferred compensation plans	1.2	$ 1.0
Proceeds from securities sold	$ 1.1	$ 0.2
Number of foreign exchange contracts held (in contracts) | contract	38
Derivative, notional amount	$ 32.1
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
Trading securities	10.0		9.7
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	50.5		47.4
Trading securities	0.0		0.0
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	5.0		4.6
Trading securities	$ 0.0		$ 0.0