Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2013

Asset Retirement Obligations [Abstract]

Schedule of Changes in Asset Retirement Obligations

		Year Ended December 31,
		2013		2012
		(in thousands)
Beginning of period total	$	235,110	$	99,347
Accretion expense		28,299		15,565
Liabilities assumed in acquisitions		23,541		132,109
Liabilities incurred		1,187		1,210
Revisions		24,586		22,308
Liabilities associated with assets sold		(3,965)		-
Liabilities settled		(53,308)		(35,429)
End of period total		255,450		235,110
Less: End of period, current portion		51,601		30,179
End of period, noncurrent portion	$	203,849	$	204,931