| Cover | Oct. 08, 2020 |
| Schedule of Capitalization, Equity [Line Items] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Amendment Description | As previously disclosed on the Form 8-K filed by Genie Energy Ltd. (the “Registrant”) with the Securities and Exchange Commission (the “SEC”) on October 9, 2020 (the “Original 8-K”), a subsidiary of the Registrant purchased the interests in Shoreditch Energy Limited (“Shoreditch”), a venture that offers electricity and natural gas service to residential and small business customers in the U.K., under the trade name Orbit Energy, that was not previously owned by the Registrant. |
| Document Period End Date | Oct. 8, 2020 |
| Entity File Number | 1-35327 |
| Entity Registrant Name | GENIE ENERGY LTD. |
| Entity Central Index Key | 0001528356 |
| Entity Tax Identification Number | 45-2069276 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 520 Broad Street |
| Entity Address, City or Town | Newark |
| Entity Address, State or Province | NJ |
| Entity Address, Postal Zip Code | 07102 |
| City Area Code | (973) |
| Local Phone Number | 438-3500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Information, Former Legal or Registered Name | Not Applicable |
| Class B common stock, par value $0.01 per share | |
| Schedule of Capitalization, Equity [Line Items] | |
| Title of 12(b) Security | Class B common stock, par value $0.01 per share |
| Trading Symbol | GNE |
| Security Exchange Name | NYSE |
| Series 2012-A Preferred stock, par value $0.01 per share | |
| Schedule of Capitalization, Equity [Line Items] | |
| Title of 12(b) Security | Series 2012-A Preferred stock, par value $0.01 per share |
| Trading Symbol | GNE.PRA |
| Security Exchange Name | NYSE |
