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Supplemental Oil and Gas Disclosures (Unaudited) - Summary of Estimated Quantities of Proved Developed Oil and Natural Gas Reserves (Detail) bbl in Thousands, Mcf in Thousands | 12 Months Ended
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Dec. 31, 2016 bbl Mcf | Dec. 31, 2015 bbl Mcf | Dec. 31, 2015 bbl Mcf | Dec. 31, 2014 bbl Mcf
Oil |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |
Beginning Balance | [1] | 5,179 | 7,672 |  |
Proved developed reserves | [1] | 446 | 5,179 | 5,179 | 5,269
Proved undeveloped reserves | [1] | 0 | 0 | 0 | 2,403
Ending Balance | [1] | 446 | 5,179 |  | 7,672
Natural Gas |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |
Beginning Balance | Mcf |  | 9,220 |  | 14,400 |
Proved developed reserves | Mcf |  | 5,035 | 9,220 | 9,220 | 12,599
Proved undeveloped reserves | Mcf |  | 0 | 0 | 0 | 1,801
Ending Balance | Mcf |  | 5,035 |  | 9,220 | 14,400
Consolidated Entities |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |
Revisions of previous estimates |  |  |  |  | 608
Consolidated Entities | Oil |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |
Beginning Balance | [1] | 5,179 | 7,672 |  | 5,824
Revisions of previous estimates | [1] | (11) | 855 |  | 608
Extensions and discoveries | [1] | 29 | 224 |  | 2,191
Acquisitions | [1] | 0 | 0 |  | 85
Sales | [1] | (4,460) | (704) |  | (105)
Production | [1] | (291) | (1,158) |  | (931)
Ending Balance | [1] | 446 | 5,179 |  | 7,672
Consolidated Entities | Natural Gas |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |
Beginning Balance | Mcf |  | 7,957 |  | 12,649 | 13,630
Revisions of previous estimates |  | 631 | 1,995 | 1,675 | 293
Extensions and discoveries | Mcf |  | 0 |  | 173 | 774
Acquisitions | Mcf |  | 0 |  | 0 | 31
Sales | Mcf |  | (3,756) |  | (1,223) | (218)
Production | Mcf |  | (996) |  | (1,967) | (1,861)
Ending Balance | Mcf |  | 3,836 |  | 7,957 | 12,649
Equity Method Investee | Oil |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |
Beginning Balance | [1] | 0 | 0 |  | 0
Revisions of previous estimates | [1] | 0 | 0 |  | 0
Production | [1] | 0 | 0 |  | 0
Ending Balance | [1] | 0 | 0 |  | 0
Equity Method Investee | Natural Gas |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |
Beginning Balance | Mcf |  | 1,263 |  | 1,751 | 2,332
Revisions of previous estimates | Mcf |  | 79 |  | (320) | (382)
Production | Mcf |  | (143) |  | (168) | (199)
Ending Balance | Mcf |  | 1,199 |  | 1,263 | 1,751
[1] | Includes natural gas liquids (NGLs).

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- Definition Proved Developed Reserves + References No definition available. + Details
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- Definition Proved Developed Reserves Acquired + References No definition available. + Details
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- Definition Proved Undeveloped Reserves + References No definition available. + Details
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- 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
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- 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
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- 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
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