Asset Retirement Obligation - Change in Asset Retirement Obligation (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2013
Asset Retirement Obligation Disclosure [Abstract]
Asset retirement obligation at beginning of period	$ 4
Additions during the period	1
Revisions of estimates	(3)
Asset retirement obligation at end of period	$ 2

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Asset Retirement Obligation

-URI http://asc.fasb.org/extlink&oid=6505190

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Period Type:	duration

- Definition

Amount of asset retirement obligations incurred during the period.

+ References

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Data Type:	xbrli:monetaryItemType
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- Definition

Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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