Derivatives and Hedging Activities - Fair Value of Derivative Instruments (Details) € in Millions, $ in Millions	Sep. 30, 2019 USD ($)	Sep. 30, 2019 EUR (€)	Dec. 31, 2018 USD ($)
Derivatives not designated as hedging instruments:
Total Derivative Assets	$ 3.9		$ 3.5
Total Derivative Liabilities	(3.5)		(2.9)
Net Derivatives	0.4		0.6
Long-term debt, less current portion	3,694.0		3,236.5
Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	3.9		3.5
Total Derivative Liabilities	(3.5)		(2.9)
Designated as Hedging Instruments | Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Long-term debt, less current portion	435.1	€ 400.0	454.9
Designated as Hedging Instruments | Cash Flow Hedge
Derivatives not designated as hedging instruments:
Total Derivative Assets	1.3		1.8
Total Derivative Liabilities	(0.3)		(0.2)
Net Derivatives	1.0		1.6
Designated as Hedging Instruments | Cash Flow Hedge | Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	1.3		1.8
Total Derivative Liabilities	(0.3)		(0.2)
Non-Designated as Hedging Instruments
Derivatives not designated as hedging instruments:
Total Derivative Assets	2.6		1.7
Total Derivative Liabilities	(3.2)		(2.7)
Net Derivatives	(0.6)		(1.0)
Non-Designated as Hedging Instruments | Foreign currency forward contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	2.6		1.7
Total Derivative Liabilities	$ (3.2)		$ (2.7)