Asset Retirement Obligations (Tables)

6 Months Ended

Jun. 30, 2020

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligation

A reconciliation of our liability for plugging and abandonment costs for the six months ended June 30, 2020 and the year ended December 31, 2019 is as follows (in thousands):

	Six Months Ended June 30,  2020			Year Ended December 31, 2019
Beginning of period	$	251,076		$	312,754
Liabilities incurred		1,618			4,063
Acquisitions		123			—
Liabilities settled		(1,416	)		(5,953	)
Disposition of wells (a)		(126,268	)		(82,576	)
Accretion expense		4,729			15,658
Change in estimate		2,507			7,130
End of period		132,369			251,076
Less current portion		(2,393	)		(2,393	)
Long-term asset retirement obligations	$	129,976		$	248,683

^(a) The six months ended June 30, 2020 primarily represents the completion of the sale of our shallow legacy assets in Northwest Pennsylvania.