Asset Retirement Obligations (Tables)

3 Months Ended

Mar. 31, 2012

Asset Retirement Obligations [Abstract]

Schedule Of Asset Retirement Obligations

	Three Months Ended March 31,
	2012			2011
	(in thousands)
Beginning asset retirement obligations	$	136,742		$	152,291
Liabilities assumed in acquisitions		—			6
New wells placed on production		830			671
Changes in estimates		—			300
Disposition of wells		—			(81	)
Liabilities settled		(5,688	)		(1,234	)
Accretion of discount from continuing operations		2,430			2,044
Accretion of discount from discontinued operations		—			692
Ending asset retirement obligations	$	134,314		$	154,689