Basis of Presentation	9 Months Ended
Sep. 30, 2018
Basis of Presentation [Abstract]
Basis of Presentation	Note 1—Basis of Presentation The accompanying unaudited consolidated financial statements of Genie Energy Ltd. and its subsidiaries (the “Company” or “Genie”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. The balance sheet at December 31, 2017 has been derived from the Company’s audited financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. For further information, please refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, as filed with the U.S. Securities and Exchange Commission (the “SEC”). The Company owns 99.3% of its subsidiary, Genie Energy International Corporation (“GEIC”), which owns 100% of Genie Retail Energy (“GRE”) and 97% of Genie Oil and Gas, Inc. (“GOGAS”). The Company is comprised of GRE, which owns and operates retail energy providers (“REPs”), including IDT Energy, Inc. (“IDT Energy”), Residents Energy, Inc. (“Residents Energy”), Town Square Energy, and Mirabito Natural Gas (“Mirabito”), and also offers energy brokerage and advisory services. Its REP businesses resell electricity and natural gas to residential and small business customers primarily in the Eastern and Midwestern United States. Internationally, GRE has begun serving customers in the United Kingdom through a joint venture and acquired a license to service customers in Japan (see Notes 7 and 8). The Company also includes Genie Oil and Gas (“GOGAS”), an oil and gas exploration company. GOGAS holds an 86.1% interest in Afek Oil and Gas, Ltd. (“Afek”), an oil and gas exploration project in the Golan Heights in Northern Israel. GOGAS also holds controlling interests in other inactive oil and gas projects. GOGAS also owned Atid Drilling Ltd., a drilling services company operating in Israel. In September 2018, the Company divested a majority interest in Atid (see Note 4). Seasonality and Weather The weather and the seasons, among other things, affect GRE’s REPs’ revenues. Weather conditions have a significant impact on the demand for natural gas used for heating and electricity used for heating and cooling. Typically, colder winters increase demand for natural gas and electricity, and hotter summers increase demand for electricity. Milder winters and/or summers have the opposite effect. Natural gas revenues typically increase in the first quarter due to increased heating demands and electricity revenues typically increase in the third quarter due to increased air conditioning use. Approximately 45% and 43% of GRE’s natural gas revenues for the relevant years were generated in the first quarters of 2017 and 2016, respectively, when demand for heating was highest. Although the demand for electricity is not as seasonal as natural gas (due, in part, to usage of electricity for both heating and cooling), approximately 30% and 31% of GRE’s electricity revenues for the relevant years were generated in the third quarters of 2017 and 2016, respectively. GRE’s REPs’ revenues and operating income are subject to material seasonal variations, and the interim financial results are not necessarily indicative of the estimated financial results for the full year.

Note 1—Basis of Presentation

The accompanying unaudited consolidated financial statements of Genie Energy Ltd. and its subsidiaries (the “Company” or “Genie”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018. The balance sheet at December 31, 2017 has been derived from the Company’s audited financial statements at that date but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. For further information, please refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017, as filed with the U.S. Securities and Exchange Commission (the “SEC”).

The Company owns 99.3% of its subsidiary, Genie Energy International Corporation (“GEIC”), which owns 100% of Genie Retail Energy (“GRE”) and 97% of Genie Oil and Gas, Inc. (“GOGAS”). The Company is comprised of GRE, which owns and operates retail energy providers (“REPs”), including IDT Energy, Inc. (“IDT Energy”), Residents Energy, Inc. (“Residents Energy”), Town Square Energy, and Mirabito Natural Gas (“Mirabito”), and also offers energy brokerage and advisory services. Its REP businesses resell electricity and natural gas to residential and small business customers primarily in the Eastern and Midwestern United States. Internationally, GRE has begun serving customers in the United Kingdom through a joint venture and acquired a license to service customers in Japan (see Notes 7 and 8). The Company also includes Genie Oil and Gas (“GOGAS”), an oil and gas exploration company. GOGAS holds an 86.1% interest in Afek Oil and Gas, Ltd. (“Afek”), an oil and gas exploration project in the Golan Heights in Northern Israel. GOGAS also holds controlling interests in other inactive oil and gas projects. GOGAS also owned Atid Drilling Ltd., a drilling services company operating in Israel. In September 2018, the Company divested a majority interest in Atid (see Note 4).

Seasonality and Weather

The weather and the seasons, among other things, affect GRE’s REPs’ revenues. Weather conditions have a significant impact on the demand for natural gas used for heating and electricity used for heating and cooling. Typically, colder winters increase demand for natural gas and electricity, and hotter summers increase demand for electricity. Milder winters and/or summers have the opposite effect. Natural gas revenues typically increase in the first quarter due to increased heating demands and electricity revenues typically increase in the third quarter due to increased air conditioning use. Approximately 45% and 43% of GRE’s natural gas revenues for the relevant years were generated in the first quarters of 2017 and 2016, respectively, when demand for heating was highest. Although the demand for electricity is not as seasonal as natural gas (due, in part, to usage of electricity for both heating and cooling), approximately 30% and 31% of GRE’s electricity revenues for the relevant years were generated in the third quarters of 2017 and 2016, respectively. GRE’s REPs’ revenues and operating income are subject to material seasonal variations, and the interim financial results are not necessarily indicative of the estimated financial results for the full year.