Income Taxes (Summary of Income Tax Uncertainties) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Liability at beginning of year, net	$ 1.3	$ 3.0	$ 3.0
Additions for tax positions of current year			0.0
Subtractions as a result of a lapse of the applicable statute of limitations	(0.4)	(1.7)	0.0
Liability at end of year, net	$ 0.9	$ 1.3	$ 3.0