Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
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)	6.00%	0.40%	4.30%	1.60%
Tax reserve adjustment (in hundredths)	(4.90%)	(0.10%)	(1.20%)	(0.50%)
Changes in certain deferred tax balances (in hundredths)	22.10%	23.20%	4.40%	10.30%
Federal research and development tax credit (in hundreths)	5.20%		1.10%
All other, net (in hundredths)	0.90%	(0.70%)	0.20%	(0.10%)
Effective tax rate (in hundredths)	64.30%	57.80%	43.80%	46.30%