Asset Retirement Obligations (Tables)

9 Months Ended

Sep. 30, 2011

Asset Retirement Obligation [Abstract]

Asset Retirement Obligations

	Nine Months
	Ended
	September 30,
	2011
Beginning of period — continuing operations	$	60,693
Liabilities incurred		2,299
Liabilities settled		(3,109	)
Accretion expense — continuing operations		3,980
Change in estimate		11,270
End of period — continuing operations	$	75,133