Asset Retirement Obligation (Tables)

9 Months Ended

Sep. 30, 2014

Asset Retirement Obligation Disclosure [Abstract]

Our asset retirement obligations primarily represent the estimated present value of the amounts we will incur to plug, abandon and remediate our producing properties at the end of their productive lives. Significant inputs used in determining such obligations include estimates of plugging and abandonment costs, estimated future inflation rates and well life. The inputs are calculated based on historical data as well as current estimated costs. A reconciliation of our liability for plugging and abandonment costs for the nine months ended September 30, 2014 is as follows (in thousands):

	Nine Months Ended September 30, 2014
Beginning of period	$	230,077
Liabilities incurred		5,475
Acquisitions		11,927
Disposition of wells		(12,121	)
Liabilities settled		(3,301	)
Change in estimate		2,455
Accretion expense		11,206
End of period		245,718
Less current portion		(5,037	)
Long-term asset retirement obligations	$	240,681