Derivatives and Hedging Activities - Fair Value of Derivative Instruments (Details) € in Millions, $ in Millions	Sep. 30, 2020 USD ($)	Sep. 30, 2020 EUR (€)	Dec. 31, 2019 USD ($)
Derivatives not designated as hedging instruments:
Total Derivative Assets	$ 6.4		$ 2.8
Total Derivative Liabilities	(3.2)		(4.0)
Net Derivatives	3.2		(1.2)
Long-term debt, less current portion	3,710.1		3,698.6
Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	6.4		2.8
Total Derivative Liabilities	(3.2)		(4.0)
Designated as hedging instruments | Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Long-term debt, less current portion	467.9	€ 400.0	445.6
Designated as hedging instruments | Cash Flow Hedge
Derivatives not designated as hedging instruments:
Total Derivative Assets	0.5		0.2
Total Derivative Liabilities	(1.1)		(2.0)
Net Derivatives	(0.6)		(1.8)
Designated as hedging instruments | Cash Flow Hedge | Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	0.5		0.2
Total Derivative Liabilities	(1.1)		(2.0)
Non-Designated as Hedging Instruments
Derivatives not designated as hedging instruments:
Total Derivative Assets	5.9		2.6
Total Derivative Liabilities	(2.1)		(2.0)
Net Derivatives	3.8		0.6
Non-Designated as Hedging Instruments | Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	5.9		2.6
Total Derivative Liabilities	$ (2.1)		$ (2.0)