Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax liabilities:
Depreciation and depletion	$ 169,404	$ 336,471
Original Issue Discount on 2025 and 2032 Notes	14,720	13,098
Equity investments in production facilities	84,870	81,082
Prepaid and other	7,556	10,548
Total deferred tax liabilities	276,550	441,199
Deferred tax assets:
Net operating loss	(40,105)	(36,981)
Asset retirement obligations	(708)	(70,085)
Reserves, accrued liabilities and other	(44,291)	(35,229)
Total deferred tax assets	(85,104)	(142,295)
Valuation allowance	22,860	16,391
Current deferred tax assets	(51,573)	(43,942)
Noncurrent deferred tax liabilities	265,879	359,237
Net deferred tax liabilities	$ 214,306	$ 315,295