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Basis of Presentation, Summary of Significant Accounting Policies and Change in Accounting Principle - Research and Development Costs (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Accounting Policies [Abstract]      
Research and development costs $ 19.8 $ 18.2 $ 17.2