Derivatives and Hedging Activities - Fair Value of Derivative Instruments (Details) € in Millions, $ in Millions	Sep. 30, 2021 USD ($)	Sep. 30, 2021 EUR (€)	Dec. 31, 2020 USD ($)
Derivatives not designated as hedging instruments:
Total Derivative Assets	$ 4.9		$ 7.3
Total Derivative Liabilities	(0.6)		(7.0)
Net Derivatives	4.3		0.3
Long-term debt, less current portion	3,315.4		3,731.4
Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	4.9		7.3
Total Derivative Liabilities	(0.6)		(7.0)
Designated as hedging instruments | Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Long-term debt, less current portion	462.6	€ 400.0	490.2
Designated as hedging instruments | Cash Flow Hedge
Derivatives not designated as hedging instruments:
Total Derivative Assets	2.8		0.0
Total Derivative Liabilities	0.0		(2.8)
Net Derivatives	2.8		(2.8)
Designated as hedging instruments | Cash Flow Hedge | Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	2.8		0.0
Total Derivative Liabilities	0.0		(2.8)
Non-Designated as Hedging Instruments
Derivatives not designated as hedging instruments:
Total Derivative Assets	2.1		7.3
Total Derivative Liabilities	(0.6)		(4.2)
Net Derivatives	1.5		3.1
Non-Designated as Hedging Instruments | Foreign currency forward and option contracts
Derivatives not designated as hedging instruments:
Total Derivative Assets	2.1		7.3
Total Derivative Liabilities	$ (0.6)		$ (4.2)