Income Taxes (Schedule Of Reconciliation Of The U.S. Federal Statutory Rate To Effective Tax Rate) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	21.00%	21.00%	21.00%
State income taxes	2.70%	3.10%	3.50%
Effective Income Tax Rate Reconciliation, Deduction, Percent	(0.50%)	(0.90%)	(0.10%)
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	0.00%	0.00%	(0.70%)
Other	0.20%	0.10%	0.30%
Effective tax rate	23.40%	23.30%	24.00%
Deferred tax asset valuation allowance, Increase (Decrease)			$ 3.4	$ 5.5