Asset Retirement Obligations

12 Months Ended

Dec. 31, 2015

Asset Retirement Obligation Disclosure [Abstract]

(8)	Asset Retirement Obligations

Our asset retirement obligations primarily represent the present value of the estimated 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 as of December 31, 2015 and 2014 are as follows (in thousands):


	2015			2014
Beginning of period	$	287,463		$	230,077
Liabilities incurred		4,595			8,602
Acquisitions		1,584			11,927
Liability released		¾			(8,309	)
Liabilities settled		(18,828	)		(4,442	)
Disposition of wells		(45,845	)		(13,951	)
Accretion expense		19,163			15,226
Change in estimate		16,005			48,333
End of period		264,137			287,463
Less current portion		(15,071	)		(15,067	)
Long-term asset retirement obligations	$	249,066		$	272,396

Accretion expense is recognized as an increase to depreciation, depletion and amortization expense in the accompanying consolidated statements of operations.