Goodwill and Other Intangible Assets Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amortization of Intangible Assets	$ 14.3	$ 11.5	$ 8.3
Future Amortization Expense, Year One	13.9
Future Amortization Expense, Year Two	13.5
Future Amortization Expense, Year Three	12.9
Future Amortization Expense, Year Four	12.4
Future Amortization Expense, Year Five	12.3
Amortization Of Acquired Intangible Asset Net Of Tax	13.3	10.9	7.4
Purchased Intangibles, Net of Tax	10.0	7.1	5.0
Capitalized Computer Software, Amortization	$ 33.0	$ 31.0	$ 27.5
Minimum [Member]
Finite-Lived Intangible Assets, Useful Life, Minimum	3 years
Maximum [Member]
Finite-Lived Intangible Assets, Useful Life, Minimum	45 years