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Business Segment Information - Additional Information (Detail) $ in Thousands | 3 Months Ended | 12 Months Ended
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Dec. 31, 2018 USD ($) | Sep. 30, 2018 USD ($) | Jun. 30, 2018 USD ($) | Mar. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Sep. 30, 2017 USD ($) | Jun. 30, 2017 USD ($) | Mar. 31, 2017 USD ($) | Dec. 31, 2018 USD ($) Segment | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Segment Reporting [Abstract] |  |  |  |  |  |  |  |  |  |  |
Current operating units | Segment |  |  |  |  |  |  |  |  | 3 |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Acquisitions of oil and gas properties |  |  |  |  |  |  |  |  |  | $ 61,874 | $ 781,522
Revenues | $ 599,755 | $ 674,629 | $ 573,751 | $ 473,812 | $ 434,875 | $ 320,283 | $ 260,809 | $ 277,752 | $ 2,321,947 | 1,293,719 | 704,665
Exploration and Production |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Acquisitions of oil and gas properties |  |  |  |  |  |  |  |  | 951,900 | 54,000 | 781,500
Revenues |  |  |  |  |  |  |  |  | 2,136,735 | 1,168,176 | 635,505
Operating segments | Exploration and Production |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | 2,136,735 | 1,168,176 | 635,505
Purchased oil and gas |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  | 172,985 | 128,064 | 67,709 | 61,547 | 36,802 | 14,919 | 20,274 | 551,808 | 133,542 | 10,272
Operating expenses |  | 174,269 | 129,579 | 70,594 | 62,043 | 37,236 | 14,698 | 20,638 | $ 554,307 | 134,615 | $ 10,258
Revision |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  | 128,181 | 72,414 | 52,596 | 30,406 | 15,535 | 6,718 | (7,364) |  | 45,295 |
Revision | Purchased oil and gas |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revenues |  | 126,629 | 70,486 | 49,672 | 30,475 | 15,607 | 6,828 | (7,357) |  | 45,553 |
Operating expenses |  | $ 128,181 | $ 72,414 | $ 52,596 | $ 30,406 | $ 15,535 | $ 6,718 | $ (7,364) |  | $ 45,295 |

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- Definition The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(a),(d)) -URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227 + Details
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- Definition Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues. + References No definition available. + Details
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- Definition The cash outflow to purchase of mineral interests in oil and gas properties for use in the normal oil and gas operations and not intended for resale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585 + Details
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