Income Taxes (Schedule Of The Reconciliation To U.S. Statutory Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Continuing operations tax (benefit) expense at statutory rate	$ (26.6)	$ 62.9	$ 51.0
Increase in valuation allowances on deferred domestic income tax assets	(0.1)	0.1	10.0
State income tax (benefit) expense, net of federal impact	(7.3)	12.4	9.2
Capital loss on sale of investment	(4.6)
Statute closures	(1.3)	(3.8)	(9.6)
State deferred tax adjustments	(1.5)	(1.9)
Capital loss utilization on WAVE earnings		(4.4)
2017 Tax Act			(1.2)
Excess tax benefits on share-based compensation	(0.9)	(3.2)	(3.8)
Tax on foreign and foreign source income		(1.9)	(4.4)
U.S. permanent differences	(2.2)	(1.8)	(1.6)
Other	1.9	(1.3)	3.5
Income tax (benefit) expense	$ (42.6)	$ 57.1	$ 53.1