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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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