Nature of Business and Accounting Policies - Goodwill Hedging Activities Foreign Currency Gain (Loss) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Number of operating segments | segment	1
Net foreign currency transaction loss | $	$ 16.1	$ 5.2	$ 1.1
Foreign currency forward contracts | Not designated as hedging instrument
Derivative [Line Items]
Derivative term	1 month