Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Taxes [Abstract]
Consolidated tax provision at federal statutory rate (in hundredths)	21.00%	21.00%
State income tax provisions, net of federal income tax benefit (in hundredths)	(1.20%)	(3.20%)
Tax reserve adjustment (in hundredths)	(2.50%)	(0.90%)
Restructuring cost	(3.40%)
Changes in certain deferred tax balances (in hundredths)	0.60%	(38.60%)
Loss on disposal of Northwest Operations (in hundreths)	(2.40%)
Shared-based payments (in hundreths)	(0.70%)	(4.40%)
Federal research and development tax credit (in hundreths)	0.60%	1.70%
All other, net (in hundredths)	(0.90%)	(1.60%)
Effective tax rate (in hundredths)	11.10%	(26.00%)