Derivative Instruments - Schedule of Outstanding Commodity Derivative Instruments (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2013 Barrels
Derivative [Line Items]
Fair value asset (liability)	$ (4,730)
2014 Two-way collar [Member]
Derivative [Line Items]
Total notional amount of oil barrels	1,510,000
Average floor price	90.77
Average ceiling price	102.06
Fair value asset (liability)	302
Settlement period	2014
2014 Swaps with subfloors [Member]
Derivative [Line Items]
Total notional amount of oil barrels	2,004,000
Average swap price	92.60
Average sub-floor price	$ 70.00
Fair value asset (liability)	(7,111)
Settlement period	2014
2014 Three-way collar [Member]
Derivative [Line Items]
Total notional amount of oil barrels	3,530,530
Average sub-floor price	$ 70.30
Average floor price	90.65
Average ceiling price	105.64
Fair value asset (liability)	2,927
Settlement period	2014
2014 Put Spreads [Member]
Derivative [Line Items]
Total notional amount of oil barrels	11,470
Average sub-floor price	$ 70.00
Average floor price	90.00
Fair value asset (liability)	0
Settlement period	2014
2014 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil barrels	2,218,500
Average swap price	95.87
Fair value asset (liability)	(2,042)
Settlement period	2014
2015 Two-way collar [Member]
Derivative [Line Items]
Total notional amount of oil barrels	108,500
Average floor price	90.00
Average ceiling price	99.86
Fair value asset (liability)	275
Settlement period	2015
2015 Three-way collars [Member]
Derivative [Line Items]
Total notional amount of oil barrels	263,500
Average sub-floor price	$ 70.59
Average floor price	90.59
Average ceiling price	105.25
Fair value asset (liability)	777
Settlement period	2015
2015 Swaps [Member]
Derivative [Line Items]
Total notional amount of oil barrels	108,500
Average swap price	93.07
Fair value asset (liability)	148
Settlement period	2015
2015 Swaps with subfloors [Member]
Derivative [Line Items]
Total notional amount of oil barrels	186,000
Average swap price	92.60
Average sub-floor price	$ 70.00
Fair value asset (liability)	$ (6)
Settlement period	2015

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

The average strike price of the sold put that establishes the price at which if the market price falls below, the minimum price would be index price plus the difference between the purchased put (floor) and the sold put strike price.

+ References

No definition available.

+ Details

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- Definition

Derivatives, Maturity Date

+ References

No definition available.

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- Definition

The average cap rate on a group of price risk derivatives such as caps or collars. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract.

+ References

No definition available.

+ Details

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- Definition

The average floor rate on a group of price risk derivatives such as floors or collars. A payment or receipt is triggered if the market rate falls below the floor rate on the contract.

+ References

No definition available.

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- Definition

Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

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- Definition

Average fixed price related to the group of price risk swap derivatives.

+ References

No definition available.

+ Details

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