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Asset Retirement Obligations (Table)

12 Months Ended

Dec. 31, 2011

Asset Retirement Obligation [Abstract]

Asset retirement obligations

(Dollars in thousands)			2011				2010
Balance, beginning of period			$	128,709			$	118,742
	Additional liabilities accrued			2,105				4,757
	Revisions in estimated cash outflows			5,888				(1,382	)
	Disposition of assets			(1,323	)			(2,086	)
	Accretion expense			8,023				8,678
Balance, end of period			$	143,402			$	128,709

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- Definition

Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Topic 410

-SubTopic 30

-Publisher FASB

-Number

-Article

-Subparagraph

-Name Accounting Standards Codification

-Paragraph 5

-Section 50

-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859

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