Basis of Presentation and Significant Accounting Policies (Details 5) (Nonrecurring Fair Value Measurments [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Total as of Period End [Member]
Fair Value Measurements [Line Items]
Oil and gas properties		$ 3,743
Other	14,000	246
Total		3,989
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member]
Fair Value Measurements [Line Items]
Oil and gas properties		0
Other	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements [Line Items]
Oil and gas properties		0
Other	0	0
Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements [Line Items]
Oil and gas properties		3,743
Other	14,000	246
Year-to-Date Impairment Losses [Member]
Fair Value Measurements [Line Items]
Oil and gas properties		15,233
Other	8,360	505
Total		$ 15,738

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Long-lived assets that are held for sale apart from normal operations and anticipated to be sold in less than one year.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 33

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- Details

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Namespace Prefix:	us-gaap_
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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This element represents the fair value of assets categorized as other which are not in and of themselves material enough to require separate disclosure.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant