Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Taxes [Abstract]
Consolidated tax provision at federal statutory rate (in hundredths)	35.00%	35.00%
State income tax provisions, net of federal income tax benefit (in hundredths)	0.20%	3.80%
Tax reserve adjustment (in hundredths)	(0.60%)
Shared Based Payments (in hundreths)	(1.80%)
Federal research and development tax credit (in hundreths)	0.90%
All other, net (in hundredths)	0.50%	(0.10%)
Effective tax rate (in hundredths)	34.20%	38.70%