Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Taxes [Abstract]
Consolidated tax provision at federal statutory rate (in hundredths)	21.00%	21.00%	21.00%	21.00%
State income tax provisions, net of federal income tax benefit (in hundredths)	1.50%	1.70%	1.50%	(34.70%)
Remeasurement of certain deferred tax balances				78.60%
Tax reserve adjustment (in hundredths)		0.90%		(1.10%)
Changes in certain deferred tax balances (in hundredths)	(1.50%)	31.60%	(1.90%)	146.60%
Goodwill impairment (in hundreths)	(10.40%)		(10.40%)
Loss on disposal of Northwest Operations (in hundreths)	(1.40%)		(1.40%)
Shared-based payments (in hundreths)			(0.10%)	(70.30%)
Federal research and development tax credit (in hundreths)		(2.20%)		(3.20%)
All other, net (in hundredths)	(0.10%)	1.00%		1.80%
Effective tax rate (in hundredths)	9.10%	54.00%	8.70%	138.70%