The aggregate amount of noncash, equity-based employee remuneration capitalized in fixed costs.

No definition available.

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- Definition

Related tax expense associated with the aggregate amount of noncash, equity-based employee remuneration recognized as expense in the Consoldiated Statements of Operations. This may include the value of stock options, amortization of restricted stock, and adjustment for officers compensation.

+ References

No definition available.

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- Definition

Lower exercise price range for options exercised during the period.

+ References

No definition available.

+ Details

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- Definition

Lower exercise price range of forfeited stock options.

+ References

No definition available.

+ Details

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- Definition

Shares of stock options exercised during the period.

+ References

No definition available.

+ Details

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- Definition

Forfeited Stock Option Shares

+ References

No definition available.

+ Details

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- Definition

Upper exercise price range for options exercised during the period.

+ References

No definition available.

+ Details

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- Definition

Upper exercise price range of forfeited stock options.

+ References

No definition available.

+ Details

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph g(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-Subparagraph b

-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.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 14.F)

-URI http://asc.fasb.org/extlink&oid=6793087&loc=d3e301413-122809

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- Definition

The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

+ Details

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- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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Share Based Compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended			12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Number Of Options [Member]	Dec. 31, 2012 Number Of Options [Member]	Mar. 31, 2013 Weighted Average Exercise Price [Member]	Dec. 31, 2012 Weighted Average Exercise Price [Member]	Dec. 31, 2011 Weighted Average Exercise Price [Member]
Valuation And Expense Information [Abstract]
Total cost of share based payment plans	$ 4,502	$ 3,681
Amounts capitalized in oil and gas properties and equipment	1,494	1,225
Share-based Compensation	3,008	2,456
Amount of related income tax benefit recognized in income before valuation allowance	$ 1,238	$ 1,011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options			1,357	1,459
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit					$ 16.97	$ 16.97	$ 16.97
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit					$ 98.87	$ 98.87	$ 98.87
Forfeited			0	(68)
Exercise Price, Lower Range Limit Forfeited					$ 0.00	$ 25.08
Exercise Price, Upper Range Limit Forfeited					$ 0.00	$ 75.18
Exercised			0	(34)
Exercise Price, Lower Range Limit Exercised					$ 0.00	$ 16.97
Exercise Price, Upper Range Limit Exercised					$ 0.00	$ 19.18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options			1,357	1,357