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Basis of Presentation (Details)	3 Months Ended
	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Mar. 31, 2015
Basis of Presentation (Textual)
Percentage of gas revenue generated in given period			43.00%		64.00%
Percentage of electricity revenue generated in given period		31.00%		29.00%
Genie Energy International Corporation [Member]
Basis of Presentation (Textual)
Company's investment, ownership percentage in subsidiary	99.30%
Genie Retail Energy [Member]
Basis of Presentation (Textual)
Company's investment, ownership percentage in subsidiary	100.00%
Ownership interest of company	2.50%
Genie Oil and Gas, Inc [Member]
Basis of Presentation (Textual)
Company's investment, ownership percentage in subsidiary	92.00%
Afek [Member]
Basis of Presentation (Textual)
Company's investment, ownership percentage in subsidiary	86.00%

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