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Property, Plant and Equipment - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		0 Months Ended	1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 26, 2013	Sep. 30, 2013 Unproved property leases [Member]	Sep. 30, 2012 Unproved property leases [Member]	Sep. 30, 2013 Unproved property leases [Member]	Sep. 30, 2012 Unproved property leases [Member]	Sep. 26, 2013 East Nesson [Member] acre	Sep. 30, 2013 West Williston Acquisition [Member]
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties	$ 56,000	$ 36,000	$ 762,000	$ 2,607,000		$ 56,000	$ 36,000	$ 762,000	$ 2,607,000
Acres acquired										25,000
Payments to acquire productive assets										54,800,000
Investment commitment	7,200,000		7,200,000		8,200,000
Acquisition, consideration transferred, deposit											$ 72,500,000

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- Definition

Business Combination, Acres Acquired

+ References

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Business Combination, Consideration Transferred, Deposit on Acquisition

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- Definition

The amount committed to invest, expend and/or incur expenses in exchange for the transfer of certain assets.

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No definition available.

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X

- Definition

The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 360

-Section 35

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=28370743&loc=d3e66150-109466



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230

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- Definition

The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

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