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Divestitures, Assets Held for Sale, and Acquisitions Divestitures and Assets Held for Sale (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 7 Months Ended |
--- | --- | --- | --- | ---
Jun. 30, 2017 | Mar. 31, 2017 | Jun. 30, 2016 | Mar. 31, 2016 | Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |
Net proceeds from the sale of oil and gas properties |  |  |  |  |  | $ 766,247 | $ 12,967 |  |
Net gain (loss) on divestiture activity |  | $ (167,133) |  | $ 50,046 |  | (129,670) | (18,975) |  |
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest |  | (190,968) |  | (264,579) |  | (72,028) | (806,664) |  |
Impairment of Proved Oil and Gas Properties |  | 3,806 |  | 0 |  | 3,806 | 269,785 |  |
Disposal Group, Including Discontinued Operation, Assets, Current |  | 18,739 |  |  |  | 18,739 |  | $ 18,739 | $ 372,621
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down |  |  |  | (49,500) | $ 68,300 |  |  |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Non-Operated Eagle Ford Divestiture 2017 [Member] |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |
Net proceeds from the sale of oil and gas properties |  |  |  |  |  | 747,400 |  |  |
Net gain (loss) on divestiture activity |  |  |  |  |  | 397,400 |  |  |
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest | [1] | 0 |  | $ 12,832 |  | 24,324 | (273,567) |  |
Impairment of Proved Oil and Gas Properties |  |  |  |  |  |  | $ 269,600 |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Divide County Divestiture 2017 [Member] |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |
Net proceeds from the sale of oil and gas properties |  | 24,600 |  |  |  |  |  |  |
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Raven/Bear Den Divestiture 2016 [Member] |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |
Net gain (loss) on divestiture activity |  |  |  |  |  |  |  | $ 29,100 |
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Divide County Disposal Group [Member] |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |
Impairment of Proved Oil and Gas Properties |  |  |  |  |  | $ 526,500 |  |  |
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down |  | $ 166,900 | $ 359,600 |  |  |  |  |  |
[1] | Income (loss) before income taxes reflects oil, gas, and NGL production revenue, less oil, gas, and NGL production expense, and depletion, depreciation, amortization, and asset retirement obligation liability accretion. Additionally, income (loss) before income taxes included impairment of proved properties expense of approximately $269.6 million for the six months ended June 30, 2016.

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