Goodwill and Other Intangibles (Narrative) (Details) - Other Intangible Assets - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]
Amortization expense related to other intangible assets	$ 4.5	$ 2.4
Estimated future amortization expense for 2018	13.4
Estimated future amortization expense for 2019	17.7
Estimated future amortization expense for 2020	17.6
Estimated future amortization expense for 2021	15.0
Estimated future amortization expense for 2022	$ 10.4