Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Deferred tax assets:
Allowance for losses and nondeductible accruals	$ 14,048		$ 15,662
Net operating loss carryforward	71,519		81,199
Non-producing oil and natural gas properties	36,416	$ 37,493
Producing oil and natural gas properties	10,495	17,044
Alternative minimum tax and research and development tax credit carryforward	1,738		1,738
Gross deferred tax assets	134,216		153,136
Valuation allowance	(46,637)		(141,365)
Total deferred tax assets	87,579		11,771
Deferred tax liabilities:
Contract drilling and other equipment	(12,354)	(11,365)
Investment in Superior	(389)		(406)
Total deferred tax liabilities	(12,743)		(11,771)
Deferred tax assets, net	$ 74,836		$ 0
Operating loss carryforwards		331,400
Operating loss carryforwards subject to expiration		$ 136,400