Derivatives and Hedging Activities - Effect of Derivative Instruments on Condensed Consolidated Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in Earnings on Derivatives	$ (6.7)	$ (3.8)	$ (8.4)	$ 1.7
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)	0.7	(1.7)	0.9
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	(1.2)	0.7	(1.8)	0.8
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	0.1	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	0.1	0.2	0.2
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	$ (5.7)	$ (4.6)	$ (6.9)	$ 0.6