Asset Retirement Obligation (Tables)

12 Months Ended

Dec. 31, 2014

Asset Retirement Obligation Disclosure [Abstract]

Schedule of Change in Asset Retirement Obligation

The following table presents the change in our gross conditional ARO (in thousands):

	December 31,
	2014			2013
Liability at January 1,	$	20,886		$	9,283
Accretion expense	1,073			745
Liabilities incurred	552			8,829
Liabilities settled	(85		)	(27		)
Revisions to cash flows	(991		)	2,056
Liability at December 31,	$	21,435		$	20,886