Description of Business and Summary of Significant Accounting Policies (Foreign Currency Translation) (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Description of Business and Summary of Significant Accounting Policies      
Foreign exchange losses, net of the foreign currency derivatives $ 1.6 $ 0.1 $ 0.6