Decommissioning and Other Asset Retirement Obligations (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Decommissioning and Other Asset Retirement Obligations Detail [Table]
Beginning balance for the period, as reported	$ 47,167,000	$ 50,904,000
Activity in the period:
Accretion of liability	181,000	371,000
Revisions in estimated cash flows	11,299,000	20,680,000
Settlement of retirement obligations	(16,459,000)	(29,767,000)
Ending balance as of June 30	42,188,000	42,188,000
Fair value of asset retirement obligations associated with non-operated properties	$ 8,100,000	$ 8,100,000	$ 7,600,000