Income Taxes (Schedule Of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets:
Allowance for doubtful accounts	$ 1,374	$ 1,046
Operating loss and tax credit carryforwards	157,395	84,684
Compensation and employee benefits	7,376	8,832
Decommissioning liabilities	39,328	39,328
Goodwill and other intangible assets	369	772
Operating leases	126	197
Other assets	52,345	30,749
Deferred tax assets, gross	258,313	165,608
Valuation allowance	(80,280)	(90,781)
Total deferred tax assets	178,033	74,827
Deferred tax liabilities:
Property, plant and equipment	64,571	64,721
Notes receivable	17,812	17,812
Other Liability	1,546	1,287
Total deferred tax liabilities	83,929	83,820
Net deferred tax liability		$ (8,993)
Net deferred tax assets (liabilities)	$ 94,104