Income Taxes (Reconciliation Of Provision For Income Taxes) (Details)	2 Months Ended	4 Months Ended	6 Months Ended
	Jun. 30, 2021	Apr. 30, 2021	Jun. 30, 2020
Successor [Member]
Consolidated tax provision at federal statutory rate	21.00%
State income tax provisions, net of federal income tax expense (benefit)	3.70%
Tax reserve adjustment	0.60%
Federal research and development tax credit	(1.30%)
All other, net	6.10%
Effective tax rate	30.10%
Predecessor [Member]
Consolidated tax provision at federal statutory rate		21.00%	21.00%
State income tax provisions, net of federal income tax expense (benefit)		0.50%	5.40%
Changes in certain deferred tax balances			(3.90%)
Interest expense deduction			10.40%
Restructuring cost		0.30%	(5.00%)
Loss on disposal of Northwest Operations			(8.00%)
Tax reserve adjustment			(0.70%)
Fresh start and reorganization adjustments		(24.90%)
Shared-based payments			(0.30%)
Federal research and development tax credit			(0.50%)
All other, net			(0.50%)
Effective tax rate		(3.10%)	17.90%