Asset Retirement Obligations (Tables)

6 Months Ended

Jun. 30, 2011

Asset Retirement Obligation [Abstract]

Asset Retirement Obligations

	Six Months
	Ended
	June 30,
	2011
Beginning of period — continuing operations	$	60,693
Liabilities incurred		1,447
Liabilities settled		(1,625	)
Accretion expense — continuing operations		2,580
Change in estimate		11,270
End of period — continuing operations	$	74,365