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Equity Investments (Narrative) (Details) $ / shares in Units, a in Thousands, $ in Thousands |  | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 05, 2017 USD ($) $ / shares shares | Oct. 31, 2016 USD ($) $ / shares shares | Sep. 30, 2017 USD ($) | Sep. 30, 2016 USD ($) | Mar. 31, 2016 USD ($) | Dec. 31, 2014 entity | Sep. 30, 2014 a | Sep. 30, 2017 USD ($) a | Sep. 30, 2016 USD ($) | Dec. 31, 2014 USD ($) | Feb. 17, 2017 $ / shares | Dec. 15, 2016 $ / shares | Feb. 29, 2016 | Feb. 01, 2016 USD ($) | Mar. 31, 2015
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments and investments in subsidiaries |  |  | $ (2,737) | $ 5,997 |  |  |  | $ (20,945) | $ (25,576) |  |  |  |  |  |
Distributions from equity method investments |  |  |  |  |  |  |  | 4,114 | 14,220 |  |  |  |  |  |
Payments for equity method investments |  |  |  |  |  |  |  | 44,844 | 18,510 |  |  |  |  |  |
Share price (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  |  |  | $ 19.48 | $ 20.96 |  |  |
IPO | Common Stock | Mammoth Energy Services LP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares sold by Mammoth Energy (in shares) | shares |  | 7,750,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Shares issued, price per share (in dollars per share) | $ / shares |  | $ 15.00 |  |  |  |  |  |  |  |  |  |  |  |  |
IPO | Common Stock | Mammoth Energy Partners LP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investment (in shares) | shares |  | 76,250 |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from sale of equity |  | $ 1,100 |  |  |  |  |  |  |  |  |  |  |  |  |
Tatex Thailand II, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments and investments in subsidiaries |  |  | $ 95 | 253 |  |  |  | $ 549 | 412 |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  | 23.50% |  |  |  |  | 23.50% |  |  |  |  |  |  |
Tatex Thailand III, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments and investments in subsidiaries |  |  | $ 0 | 0 |  |  |  | $ 0 | 0 |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  | 17.90% |  |  |  |  | 17.90% |  |  |  |  |  |  |
Grizzly Oil Sands ULC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gas and oil area, reserve (acres) | a |  |  |  |  |  |  |  | 830 |  |  |  |  |  |  |
Income (loss) from equity method investments and investments in subsidiaries |  |  | $ (296) | (363) |  |  |  | $ (869) | (24,811) |  |  |  |  |  |
Other than temporary impairment loss |  |  |  |  | $ 23,100 |  |  |  |  |  |  |  |  |  |
Equity method investment, amount of cash calls, based on proportionate ownership interest |  |  |  |  |  |  |  | 1,800 |  |  |  |  |  |  |
Equity method investments, increase (decrease) due to foreign currency translation adjustment |  |  | $ 6,700 | (1,400) |  |  |  | $ 12,500 | 8,300 |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  | 24.9999% |  |  |  |  | 24.9999% |  |  |  |  |  |  |
Grizzly Oil Sands ULC | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investments, fair value of minority interest |  |  |  |  | $ 39,100 |  |  |  |  |  |  |  |  |  |
Windsor Midstream LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments and investments in subsidiaries |  |  | $ 2 | 9,014 |  |  |  | $ (25,232) | 12,062 |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  | 22.50% |  |  |  |  | 22.50% |  |  |  |  |  |  |
Loss from equity method investment, net of related out-of-pocket activity |  |  |  |  |  |  |  | $ 23,400 |  |  |  |  |  |  |
Distributions from equity method investments |  |  |  |  |  |  |  | 500 | 14,200 |  |  |  |  |  |
Coronado Midstream LLC | Windsor Midstream LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 28.40%
Sturgeon Acquisitions LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments and investments in subsidiaries |  |  | $ 0 | (112) |  |  |  | $ 71 | (623) |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  | 0.00% |  |  | 25.00% |  | 0.00% |  | 25.00% |  |  |  |  |
Payments for equity method investments |  |  |  |  |  |  |  |  |  | $ 20,700 |  |  |  |  |
Gain on sale of equity method investments | $ 12,500 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mammoth Energy Services LP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investments, increase (decrease) due to foreign currency translation adjustment |  |  | $ 160 | 200 |  |  |  | $ 200 | (1,100) |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  | 25.10% |  |  | 30.50% |  | 25.10% |  | 30.50% |  |  |  |  |
Number of entities contributed for ownership interest | entity |  |  |  |  |  | 4 |  |  |  |  |  |  |  |  |
Shares received from equity method investee in exchange for ownership interest (in shares) | shares | 2,000,000 | 9,150,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Share price (in dollars per share) | $ / shares | $ 18.50 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Mammoth Energy Services LP | IPO | Common Stock | Mammoth Energy Services LP |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares sold by Mammoth Energy (in shares) | shares |  | 7,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Mammoth Energy Services LP | IPO | Common Stock | Certain selling stockholders |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares sold by Mammoth Energy (in shares) | shares |  | 250,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Strike Force Midstream LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income (loss) from equity method investments and investments in subsidiaries |  |  | $ (127) | $ 99 |  |  |  | $ (2,585) | 40 |  |  |  |  |  |
Equity method investment, amount of cash calls, based on proportionate ownership interest |  |  |  |  |  |  |  | $ 43,000 |  |  |  |  |  |  |
Equity method investment, ownership interest, percent |  |  | 25.00% |  |  |  |  | 25.00% |  |  |  |  | 25.00% |  |
Distributions from equity method investments |  |  |  |  |  |  |  | $ 3,600 | $ 4,000 |  |  |  |  |  |
Strike Force Midstream LLC | Level 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity method investments, fair value of minority interest |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 22,500 |
Phu Horm Field | Apico Llc |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gas and oil area, reserve (acres) | a |  |  |  |  |  |  |  | 180 |  |  |  |  |  |  |
Concession Acreage in Southeast Asia | Tatex Thailand III, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gas and oil area, reserve (acres) | a |  |  |  |  |  |  | 245 |  |  |  |  |  |  |  |
Apico Llc | Tatex Thailand II, LLC |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage |  |  | 8.50% |  |  |  |  | 8.50% |  |  |  |  |  |  |
Strike Force Midstream LLC | Rice Energy Inc |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage by parent |  |  |  |  |  |  |  |  |  |  |  |  | 75.00% |  |

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