v3.10.0.1

Derivative Instruments and Fair Value Measurements - Summary of Commodity Derivatives (Loss) Gain (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
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Sep. 30, 2018 | Sep. 30, 2017 | Sep. 30, 2018 | Sep. 30, 2017
Derivatives Not Designated as Hedging Instruments [Member] |  |  |  |
Derivatives Fair Value [Line Items] |  |  |  |
Commodity derivative (loss) gain | $ (3,256) | $ (3,560) | $ (10,068) | $ 1,115
Derivatives Not Designated as Hedging Instruments [Member] | Net Cash (Payment) Receipt on Derivatives Settlements [Member] |  |  |  |
Derivatives Fair Value [Line Items] |  |  |  |
Commodity derivative (loss) gain | (3,172) | (523) | (6,685) | (1,481)
Derivatives Not Designated as Hedging Instruments [Member] | Non-Cash Fair Value (Loss) Gain on Derivatives [Member] |  |  |  |
Derivatives Fair Value [Line Items] |  |  |  |
Commodity derivative (loss) gain | (84) | $ (3,037) | (3,383) | $ 2,596
Derivatives Designated as Hedging [Member] | Cash Flow Hedges [Member] | Oil, NGLs and Gas Sales [Member] |  |  |  |
Derivatives Fair Value [Line Items] |  |  |  |
Commodity derivative (loss) gain | $ (85) |  | $ (23) |

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- Definition Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959 + Details
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