Asset Retirement Obligation

9 Months Ended

Sep. 30, 2011

Asset Retirement Obligation [Abstract]

Asset Retirement Obligation

Note 9 — Asset Retirement Obligation

Following are reconciliations of the beginning and ending asset retirement obligation for the following periods (in thousands):

	Nine Months Ended
	September 30,
	2011			2010
Asset retirement obligation, beginning of period	$	166,858		$	150,199
Liabilities incurred		4,074			1,491
Liabilities settled		(25,602	)		(2,890	)
Property dispositions		—			(242	)
Accretion of asset retirement obligation		11,157			10,419
Changes in estimates		256			(182	)
Total asset retirement obligation		156,743			158,795
Less current portion		(61,255	)		(46,984	)
Total long-term asset retirement obligation, end of period	$	95,488		$	111,811