Details Of Certain Accounts (Accrued Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Details Of Certain Accounts [Abstract]
Accrued payroll and related benefits	$ 54,147	$ 49,599
Royalties payable	13,061	19,391
Current asset retirement obligations (Note 4)	67,302	93,183
Unearned revenue	8,264	7,654
Billing in excess of cost	7,317	28,839
Accrued interest	9,292	24,028
Hedging liability (Note 16)	20,333	1,247
Gas and oil imbalance	3,167	4,177
Taxes payable excluding income tax payable	5,689	3,761
Other	7,717	8,084
Total accrued liabilities	$ 196,289	$ 239,963