XML 136 R120.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Estimated quantities of proved reserves (Details 3) | 12 Months Ended
--- | ---
Dec. 31, 2016 MBoe MMcf MBbls | Dec. 31, 2015 MBoe MMcf MBbls | Dec. 31, 2014 MBoe MMcf MBbls
Proved developed and undeveloped reserves: |  |  |
Balance at beginning of year, BOE | MBoe | 13,321 | 91,940 | 80,695
Production, BOE | MBoe | 0 | (6,471) | (8,998)
Extensions and discoveries, BOE | MBoe | 0 | 888 | 24,025
Improved recovery, BOE | MBoe | 0 | 0 | 0
Purchases of proved reserves, BOE | MBoe | 0 | 0 | 6,748
Sales revisions, BOE | MBoe | (13,321) | (57,097) | (14,796)
Revisions of previous estimate, BOE | MBoe | 0 | (15,939) | 4,266
Balance at end of year, BOE | MBoe | 0 | 13,321 | 91,940
Oil (MBbls) |  |  |
Proved developed and undeveloped reserves: |  |  |
Balance at beginning of year | 12,687 | 43,918 | 41,019
Production | 0 | (3,286) | (4,919)
Extensions and discoveries | 0 | 744 | 9,654
Improved recovery | 0 | 0 | 0
Purchases of proved reserves | 0 | 0 | 5,463
Sales of proved reserves | (12,687) | (16,474) | (4,945)
Revisions of previous estimates | 0 | (12,215) | (2,354)
Balance at end of year | 0 | 12,687 | 43,918
NGL (MBbls) |  |  |
Proved developed and undeveloped reserves: |  |  |
Balance at beginning of year | 211 | 7,187 | 6,602
Production | 0 | (393) | (609)
Extensions and discoveries | 0 | 29 | 3,634
Improved recovery | 0 | 0 | 0
Purchases of proved reserves | 0 | 0 | 0
Sales of proved reserves | (211) | (6,864) | (3,109)
Revisions of previous estimates | 0 | 252 | 669
Balance at end of year | 0 | 211 | 7,187
Natural Gas (MMcf) |  |  |
Proved developed and undeveloped reserves: |  |  |
Balance at beginning of year | MMcf | 2,531 | 245,011 | 198,445
Production | MMcf | 0 | (16,747) | (20,822)
Extensions and discoveries | MMcf | 0 | 681 | 64,420
Improved recovery | MMcf | 0 | 0 | 0
Purchases of proved reserves | MMcf | 0 | 0 | 7,711
Sales of proved reserves | MMcf | (2,531) | (202,560) | (40,451)
Revisions of previous estimates | MMcf | 0 | (23,854) | 35,708
Balance at end of year | MMcf | 0 | 2,531 | 245,011

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_IncreaseDecreaseInProvedDevelopedAndUndevelopedReservesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Energy measure of increase in quantity of proved reserve of oil and gas resulting from the extension of the proved acreage of previously discovered reservoir or discovery of new field with proved reserve or of new reservoir of proved reserve in old field, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReserveExtensionAndDiscoveryEnergy
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Energy measure of increase in quantity of proved reserve of oil and gas resulting from application of improved recovery techniques, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReserveImprovedRecoveryEnergy
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Energy measure of proved reserve of oil and gas, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReserveNetEnergy
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | instant

X
- Definition Energy measure of decrease in quantity of proved reserve of oil and gas resulting from production, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReserveProductionEnergy
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Energy measure of increase in quantity of proved reserve of oil and gas resulting from purchase of mineral in place, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservePurchaseOfMineralInPlaceEnergy
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Energy measure of increase (decrease) in quantity of proved reserve of oil and gas related to revision of a previous estimate resulting from new information, except for an increase in proved acreage, or change in economic factors, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReserveRevisionOfPreviousEstimateEnergy
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Additions to proved reserves that result from (1) extension of the proved acreage of previously discovered (old) reservoirs through additional drilling in periods after discovery and (2) discovery of new fields with proved reserves or of new reservoirs of proved reserves in old fields. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesExtensionsDiscoveriesAndAdditions
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Changes in proved reserve estimates resulting from application of improved recovery techniques. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesImprovedRecovery
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition The net quantity of proved reserves as of the balance sheet date. Proved oil reserves are the estimated quantities of crude oil and natural gas liquids which geological and engineering data demonstrate with reasonable certainty to be recoverable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-10.(a)(2)) -URI http://asc.fasb.org/extlink&oid=50486907&loc=d3e511914-122862 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesNet
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | instant

X
- Definition Production of proved reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesProduction
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Purchase of minerals in place. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesPurchasesOfMineralsInPlace
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revisions represent changes in previous estimates of proved reserves, either upward or downward, resulting from new information (except for an increase in proved acreage) normally obtained from development drilling and production history or resulting from change in economic factors. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesRevisionsOfPreviousEstimatesIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Energy measure of decrease in quantity of proved reserve of oil and gas resulting from sale of mineral in place, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesSaleOfMineralInPlaceEnergy
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Sales of minerals in place. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61831-109447 + Details
Name: | us-gaap_ProvedDevelopedAndUndevelopedReservesSalesOfMineralsInPlace
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ReserveQuantitiesByTypeOfReserveAxis=us-gaap_OilReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReserveQuantitiesByTypeOfReserveAxis=us-gaap_NaturalGasLiquidsReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReserveQuantitiesByTypeOfReserveAxis=us-gaap_NaturalGasReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |