INCOME TAXES (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Allowance for losses and nondeductible accruals	$ 23,819	$ 22,051
Net operating loss carryforward	94,441	100,236
Depreciation, depletion, amortization, and impairment	68,001	80,947
Alternative minimum tax and research and development tax credit carryforward	1,738	1,738
Deferred tax assets, total	187,999	204,972
Investment in Superior	(3,626)	(3,987)
Net deferred tax asset	184,373	200,985
Valuation allowance	(184,373)	(200,985)
Non-current-deferred tax liability	$ 0	$ 0