Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2012

Asset Retirement Obligations [Abstract]

Schedule Of Change In Asset Retirement Obligation

	Year Ended		Year Ended
	December 31,		December 31,
	2012		2011
Beginning of period	$	92,561	$	69,230
Assumed in acquisitions		14,581		-
Revisions to previous estimates (1)		17,278		18,609
Liabilities incurred		1,185		377
Liabilities settled		(4,262)		(248)
Accretion expense		5,648		4,593
End of period	$	126,991	$	92,561
Less: Current portion of asset retirement obligations		(1,426)		(348)
Asset retirement obligations - non current	$	125,565	$	92,213

In 2012, we recorded an upward revision to previous estimates for our asset retirement obligations primarily due to changes in the estimated abandonment dates. In 2011, we recorded upward revisions to previous estimates for our asset retirement obligations due to increases in future plugging and abandonment costs and changes to the remaining lives of our wells.