Fair Value Measurements (Summary Of Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives - foreign exchange contracts, Liabilities	$ 0.0	$ 0.1
Estimated fair value of long-term debt	$ 816.0	$ 801.8