Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Consolidated tax provision at federal statutory rate	21.00%	35.00%	35.00%
State income tax provisions, net of federal income tax benefit	1.60%	1.70%	(0.10%)
Tax reserve adjustment	0.10%	0.10%	0.60%
Domestic production activities deduction			(1.90%)
Changes in certain deferred tax balances	(3.50%)	(0.40%)	5.80%
Goodwill impairment	(10.40%)	(19.10%)
Share-based payments	0.50%
Federal research and development credit	0.10%	0.10%	1.00%
Deferred Tax Remeasurement - 2017 Tax Reform	0.60%	26.10%
All other, net	(0.20%)	(0.10%)	(0.20%)
Effective tax rate	8.80%	43.40%	40.20%