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Supplemental Oil and Gas Reserve Information - Unaudited - Additional Information (Detail) | 1 Months Ended | 12 Months Ended
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Mar. 31, 2014 MBoe | Dec. 31, 2015 location MBoe $ / bbl $ / MMBTU | Dec. 31, 2014 location MBoe $ / bbl $ / MMBTU | Dec. 31, 2013 MBoe $ / bbl $ / MMBTU
Oil and Gas Exploration and Production Industries Disclosures [Abstract] |  |  |  |
Purchases of reserves in place (Energy) |  | 2,565 | 1,799 | 45,731
Additions due to extensions and discoveries (Energy) |  | 46,640 | 92,596 | 46,094
Estimated extensions and discoveries of reserves associated with new wells (Energy) |  | 20,362 | 34,404 | 22,190
Percentage of reserves produced from wells in certain formations |  | 100.00% | 100.00% | 100.00%
Additional proved undeveloped reserves (Energy) |  | 26,278 | 58,192 | 23,904
Percentage of proved undeveloped reserves |  | 100.00% | 100.00% | 100.00%
Divested reserves associated with non-operated properties (Energy) | 8,448 | 0 | 8,448 | 0
Net positive (negative) revisions of previous estimates (Energy) |  | (84,635) | (25,117) | 5,125
Percentage of net positive (negative) revisions |  | (31.00%) | (11.00%) | 4.00%
Proved undeveloped locations | location |  | 259 | 80 |
Proved undeveloped locations, net | location |  | 190.8 | 56.2 |
Proved undeveloped reserves, decrease (Energy) |  | 71,945 | 21,411 |
Discount rate of future cash flows |  | 10.00% |  |
Unweighted arithmetic average first-day-of-the-month prices for oil, price per Bbl | $ / bbl |  | 50.16 | 95.28 | 96.96
Unweighted arithmetic average first-day-of-the-month prices for natural gas, price per MMBtu | $ / MMBTU |  | 2.63 | 4.35 | 3.66

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