The difference between the carrying value and the sale price of real estate or properties that were intended to be sold or held for capital appreciation or rental income. This element refers to the gain (loss) included in earnings and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

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- 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

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

-Publisher FASB

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- Definition

The cash inflow to dispose of long-lived, physical assets and mineral interests in oil and gas properties used for normal oil and gas operations.

+ 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

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Property, Plant and Equipment - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 05, 2014	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties	$ 5,321,000us-gaap_ImpairmentOfOilAndGasProperties	$ 762,000us-gaap_ImpairmentOfOilAndGasProperties
Gain on sale of properties	0us-gaap_GainLossOnSaleOfProperties	183,393,000us-gaap_GainLossOnSaleOfProperties
Unproved property leases [Member]
Property, Plant and Equipment [Line Items]
Impairment of oil and gas properties	5,300,000	800,000
Non-Operated Oil and Natural Gas Properties [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of properties			324,900,000
Gain on sale of properties				$ 187,000,000