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Equity Investments (Narrative) (Details) a in Thousands |  | 1 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jan. 28, 2014 USD ($) | Mar. 31, 2015 USD ($) | Jun. 30, 2016 USD ($) | Jun. 30, 2015 USD ($) | Mar. 31, 2015 USD ($) | Jun. 30, 2016 USD ($) a shares | Jun. 30, 2015 USD ($) | Dec. 31, 2014 USD ($) | Mar. 31, 2016 USD ($) | Dec. 31, 2012 | Oct. 05, 2012 USD ($)
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Impairment of oil and gas properties |  |  | $ 170,621,000 | $ 0 |  | $ 389,612,000 | $ 0 |  |  |  |
Income (loss) from equity method investments |  |  | (836,000) | (15,120,000) |  | (31,573,000) | 4,855,000 |  |  |  |
Distributions from equity method investments |  |  |  |  |  | 4,658,000 | 4,612,000 |  |  |  |
Payments for equity method investments |  |  |  |  |  | $ 16,690,000 | 8,267,000 |  |  |  |
Investment in Tatex Thailand II, LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Equity shares owned by affiliate (shares) | shares |  |  |  |  |  | 85,122 |  |  |  |  |
Total shares owned of subaffiliate (shares) | shares |  |  |  |  |  | 1,000,000 |  |  |  |  |
Gas and oil area, reserve (acres) | a |  |  |  |  |  | 243 |  |  |  |  |
Income (loss) from equity method investments |  |  | $ 0 | 0 |  | $ 159,000 | 0 |  |  |  |
Ownership interest, percent |  |  | 23.50% |  |  | 23.50% |  |  |  |  |
Investment in Tatex Thailand III, LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Gas and oil area, reserve (acres) | a |  |  |  |  |  | 245 |  |  |  |  |
Income (loss) from equity method investments |  |  | $ 0 | (189,000) |  | $ 0 | (189,000) |  |  |  |
Ownership interest, percent |  |  | 17.90% |  |  | 17.90% |  |  |  |  |
Investment in Grizzly Oil Sands ULC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Gas and oil area, reserve (acres) | a |  |  |  |  |  | 830 |  |  |  |  |
Impairment of oil and gas properties |  |  |  |  |  | $ 23,100,000 |  |  |  |  |
Income (loss) from equity method investments |  |  | $ (763,000) | (8,494,000) |  | (24,448,000) | (12,636,000) |  |  |  |
Equity method investment, amount of cash calls, based on proportionate ownership interest |  |  |  |  |  | 13,700,000 |  |  |  |  |
Equity Method Investments, Increase (Decrease) Due To Foreign Currency Translation Adjustment |  |  | $ (600,000) | 3,200,000 |  | $ 9,700,000 | 11,700,000 |  |  |  |
Ownership interest, percent |  |  | 24.9999% |  |  | 24.9999% |  |  |  |  |
Investment in Windsor Midstream LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments |  |  | $ 2,881,000 | (881,000) |  | $ 3,048,000 | 17,906,000 |  |  |  |
Distributions from equity method investments |  |  |  |  |  | $ 4,900,000 |  |  |  |  |
Ownership interest, percent |  |  | 22.50% |  |  | 22.50% |  |  |  |  |
Investment in Windsor Midstream LLC | MidMar Gas LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Ownership interest, percent |  |  |  |  |  |  |  |  |  | 28.40% |
Coronado Midstream | Investment in Windsor Midstream LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of interest in partnership unit |  | $ 600,000,000 |  |  |  |  |  |  |  |  |
Gain on sale on investment |  | $ 81,600,000 |  |  |  |  |  |  |  |  |
Investment in Blackhawk Midstream LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments |  |  | $ 0 | 0 |  | $ 0 | 7,217,000 |  |  |  |
Ownership interest, percent |  |  | 48.50% |  |  | 48.50% |  |  |  |  |
Investment in Blackhawk Midstream LLC | Ohio Gathering Company, LLC and Ohio Condensate Company, LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Purchase price of sold equity interests | $ 190,000,000 |  |  |  |  |  |  |  |  |  |
Amount put in escrow | $ 14,300,000 |  |  |  |  |  |  |  |  |  |
Proceeds from release of escrow deposits |  |  |  |  | $ 7,200,000 |  |  |  |  |  |
Investment in Sturgeon Acquisitions LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments |  |  | $ (134,000) | 491,000 |  | $ (511,000) | 1,059,000 |  |  |  |
Ownership interest, percent |  |  | 25.00% |  |  | 25.00% |  |  |  |  |
Payments for equity method investments |  |  |  |  |  |  |  | $ 20,700,000 |  |  |
Investment in Mammoth Energy Partners LP |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments |  |  | $ (2,543,000) | (5,624,000) |  | $ (9,009,000) | (7,996,000) |  |  |  |
Equity Method Investments, Increase (Decrease) Due To Foreign Currency Translation Adjustment |  |  |  |  |  | $ (1,300,000) |  |  |  |  |
Ownership interest, percent |  |  | 30.50% |  |  | 30.50% |  |  |  |  |
Investment in Strike Force Midstream LLC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments |  |  | $ (59,000) | $ 0 |  | $ (59,000) | $ 0 |  |  |  |
Equity method investment, amount of cash calls, based on proportionate ownership interest |  |  |  |  |  | $ 3,000,000 |  |  |  |  |
Ownership interest, percent |  |  | 25.00% |  |  | 25.00% |  |  |  |  |
Investment in Strike Force Midstream LLC | Rice Energy Inc |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Ownership interest, percent |  |  | 75.00% |  |  | 75.00% |  |  |  |  |
Revolving Credit Facility | Subsidiaries |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Revolving credit facility |  |  |  |  |  |  |  |  |  |  | $ 125,000,000.0
Credit facility outstanding |  |  | $ 57,200,000 |  |  | $ 57,200,000 |  |  |  |  |
Level 3 | Investment in Grizzly Oil Sands ULC |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |
Equity investment at fair value |  |  |  |  |  |  |  |  | $ 39,100,000 |  |

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Data Type: | na
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