Asset Retirement Obligations (Details) (USD $)
In Millions, unless otherwise specified |
Sep. 30, 2012
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Dec. 31, 2011
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Asset retirement obligations: | ||
Asset retirement obligations | $ 23.9 | $ 27.0 |
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- Definition
The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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