Derivatives and Hedging Activities - Effect of Derivative Instruments on Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Derivatives	$ 0.4	$ (16.2)	$ (8.5)	$ (11.7)
Derivatives designated as hedging instruments | Cash Flow Hedge
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Derivatives	1.1	(0.1)	(0.6)	0.8
Derivatives designated as hedging instruments | Cash Flow Hedge | Foreign currency forward contracts
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Derivatives	1.1	(0.1)	(0.7)	0.7
Derivatives designated as hedging instruments | Cash Flow Hedge | Treasury locks
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Derivatives	0.0	0.0	0.1	0.1
Derivatives designated as hedging instruments | Fair Value Hedges | Interest rate swaps
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Derivatives	0.1	0.2	0.4	0.4
Derivatives not designated as hedging instruments | Foreign currency forward contracts
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Derivatives	$ (0.8)	$ (16.3)	$ (8.3)	$ (12.9)