Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2011

Asset Retirement Obligations [Abstract]

ARO operating costs

		$205,088		$205,088		$205,088
in thousands	2011		2010		2009
ARO Operating Costs
Accretion		$8,195		$8,641		$8,802
Depreciation		7,242		11,516		13,732
Total		$15,437		$20,157		$22,534

Reconciliations of ARO

in thousands	2011			2010
Asset Retirement Obligations
Balance at beginning of year		$162,730			$167,757
Liabilities incurred		1,738			2,501
Liabilities settled		(16,630	)		(11,354	)
Accretion expense		8,195			8,641
Revisions up (down), net		(2,054	)		(4,815	)
Balance at end of year		$153,979			$162,730