Asset Retirement Obligations (Tables)

9 Months Ended

Sep. 30, 2011

Asset Retirement Obligations [Abstract]

Asset Retirement Obligations

(in thousands)
Asset retirement obligation at January 1, 2011	$	50,292
Activity during the nine months ended September 30, 2011:
Adjustment to liability due to acquisitions		1,684
Liabilities incurred during the period		3,369
Liabilities settled during the period		(115	)
Adjustment to liability due to property sales		(982	)
Accretion of discount		2,728
Asset retirement obligations at September 30, 2011		56,976
Less current portion		(1,279	)
Long-term portion	$	55,697