Derivatives and Hedging Activities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Foreign Currency Cash Flow Hedge Asset at Fair Value	$ 4.0		$ 4.0		$ 0.5
Derivative, Notional Amount	400.8		400.8		386.9
Foreign Currency Cash Flow Hedge Liability at Fair Value	0.6		0.6		2.1
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	3.9		3.9		0.8
Derivative Asset	7.9		7.9		1.3
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Liability at Fair Value	1.0		1.0		5.0
Derivative Liability	1.6		1.6		$ 7.1
Unrealized Gain on Foreign Currency Derivatives, before Tax	4.4	$ 2.0	4.0	$ 3.1
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(0.2)	0.4	(1.4)	0.7
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	(0.2)	(0.1)	(0.4)	(0.2)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	(0.4)	0.3	(1.8)	0.5
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 11.0	$ (7.2)	$ 6.7	$ 8.3