Guarantee	9 Months Ended
Sep. 30, 2011
Guarantee [Abstract]
Guarantee	(15) Guarantee As part of SPN Resources’ acquisition of its oil and gas properties while a wholly-owned subsidiary of the Company, the Company guaranteed SPN Resources’ performance of its decommissioning liabilities. These guarantees remain in place. In connection with the Company’s contribution of its remaining equity interest in SPN Resources to DOH in March 2011, DOR assumed all of the Company’s obligations relating to its guarantees of SPN Resources’ performance of its decommissioning liabilities. In accordance with authoritative guidance related to guarantees, the Company has assigned an estimated value of $2.6 million at September 30, 2011 and December 31, 2010 related to decommissioning performance guarantees, which is reflected in other long-term liabilities. The Company believes that the likelihood of being required to perform these guarantees is remote. In the unlikely event that DOR defaults on the decommissioning liabilities, the total maximum potential obligation under these guarantees is estimated to be approximately $109.2 million, net of the contractual right to receive payments from third parties, which is approximately $24.6 million as of September 30, 2011. The total maximum potential obligation will decrease over time as the underlying obligations are fulfilled by DOR.

(15) Guarantee

As part of SPN Resources’ acquisition of its oil and gas properties while a wholly-owned subsidiary of the Company, the Company guaranteed SPN Resources’ performance of its decommissioning liabilities. These guarantees remain in place. In connection with the Company’s contribution of its remaining equity interest in SPN Resources to DOH in March 2011, DOR assumed all of the Company’s obligations relating to its guarantees of SPN Resources’ performance of its decommissioning liabilities. In accordance with authoritative guidance related to guarantees, the Company has assigned an estimated value of $2.6 million at September 30, 2011 and December 31, 2010 related to decommissioning performance guarantees, which is reflected in other long-term liabilities. The Company believes that the likelihood of being required to perform these guarantees is remote. In the unlikely event that DOR defaults on the decommissioning liabilities, the total maximum potential obligation under these guarantees is estimated to be approximately $109.2 million, net of the contractual right to receive payments from third parties, which is approximately $24.6 million as of September 30, 2011. The total maximum potential obligation will decrease over time as the underlying obligations are fulfilled by DOR.