Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Taxes [Abstract]
Consolidated tax provision at federal statutory rate (in hundredths)	35.00%	35.00%	35.00%	35.00%
State income tax provisions, net of federal income tax benefit (in hundredths)	1.80%	6.00%	1.60%	4.30%
Tax reserve adjustment (in hundredths)	(0.10%)	(4.90%)	(0.10%)	(1.20%)
Changes in certain deferred tax balances (in hundredths)	(0.30%)	22.10%	(0.20%)	4.40%
Goodwill impairment (in hundreths)	12.30%		10.90%
Shared-based payments (in hundreths)			(0.20%)
Federal research and development tax credit (in hundreths)	0.10%	5.20%	0.20%	1.10%
All other, net (in hundredths)	(0.20%)	0.90%	(0.20%)	0.20%
Effective tax rate (in hundredths)	24.00%	64.30%	25.20%	43.80%