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Basis of Presentation (Details) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Mar. 31, 2017 | Sep. 30, 2016 | Mar. 31, 2016 | Sep. 30, 2018
Genie Retail Energy [Member] |  |  |  |
Basis of Presentation (Textual) |  |  |  |
Company's investment, ownership percentage in subsidiary |  |  |  | 100.00%
Percentage of gas revenue generated in given period | 45.00% |  | 43.00% |
Percentage of electricity revenue generated in given period |  | 31.00% |  |
Genie Oil and Gas, Inc. [Member] |  |  |  |
Basis of Presentation (Textual) |  |  |  |
Company's investment, ownership percentage in subsidiary |  |  |  | 97.00%
Afek Oil and Gas, Ltd. [Member] |  |  |  |
Basis of Presentation (Textual) |  |  |  |
Company's investment, ownership percentage in subsidiary |  |  |  | 86.10%
Genie Energy International Corporation [Member] |  |  |  |
Basis of Presentation (Textual) |  |  |  |
Company's investment, ownership percentage in subsidiary |  |  |  | 99.30%

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