Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Allowance for losses and nondeductible accruals	$ 77,285	$ 74,890
Net operating loss carryforward	61,055	56,020
Alternative minimum tax credit carryforward	17,258	1,972
Deferred tax assets, total	155,598	132,882
Depreciation, depletion, amortization and impairment	(943,411)	(819,893)
Net deferred tax liability	(787,813)	(687,011)
Current deferred tax asset	13,585	8,765
Non-current-deferred tax liability	$ (801,398)	$ (695,776)