Details Of Certain Accounts (Other Current Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Details Of Certain Accounts [Abstract]
Other receivables	$ 4,771	$ 5,096
Prepaid insurance	6,637	12,701
Other prepaids	10,200	13,271
Spare parts inventory	16,614	18,066
Current deferred tax assets	44,442	41,449
Hedging assets	17,785	21,579
Gas and oil imbalance	4,175	5,134
Other	5,045	4,325
Other current assets	$ 109,669	$ 121,621