| In millions, except per share items | Dec-31-22 | Dec-31-21 | Dec-31-20 | Dec-31-19 | Dec-31-18 | Dec-31-17 | Dec-31-16 | Dec-31-15 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Revenues: | | | | | | | | |
| Total revenues | 315.5 | 323.3 | 356.9 | 315.3 | 0.2 | 264.2 | 212.1 | 213.1 |
| Total revenues growth | -2.4% | -9.4% | 13.2% | 185365.3% | -99.9% | 24.6% | -0.4% | -24.2% |
| Cost of revenues | 160.8 | 231.6 | 261.9 | 232.4 | 203.8 | 178.7 | 135.2 | 146.4 |
| Gross profit | 154.8 | 91.6 | 95.1 | 82.9 | 76.5 | 85.5 | 76.9 | 66.6 |
| Gross margin | 49.1% | 28.3% | 26.6% | 26.3% | 45027.6% | 32.4% | 36.3% | 31.3% |
| |
| Operating expenses: | | | | | | | | |
| Selling, general and administrative (i) | 75.0 | 67.5 | 71.8 | 72.7 | 61.5 | 80.1 | 61.6 | 66.0 |
| Income from operations | 77.8 | 24.1 | 21.9 | 9.8 | 12.0 | -6.0 | -30.5 | -8.3 |
| Operating margin | 24.6% | 7.5% | 6.1% | 3.1% | 7045.9% | -2.3% | -14.4% | -3.9% |
| Interest income | 0.8 | 0.0 | 0.2 | 0.4 | 0.6 | 0.3 | 0.3 | 0.4 |
| Interest expense | -0.1 | -0.4 | -0.3 | -0.5 | -0.4 | -0.3 | 0.0 | 0.0 |
| |
| Gain (loss) on marketable equity securities and investments | | | | | | | | |
| Gain on sale of subsidiary | | | | | | | | |
| Other (loss) income, net | -0.5 | 0.7 | 0.4 | 1.1 | 0.2 | -0.4 | 0.2 | -0.2 |
| Income before income taxes | 77.5 | 23.7 | 22.4 | 6.0 | 9.0 | -6.9 | -30.0 | -8.1 |
| Provision for income taxes | -21.0 | -7.5 | -7.6 | -4.6 | 12.4 | -1.7 | -2.2 | -0.5 |
| Net income | 86.9 | 27.8 | 15.6 | 1.4 | 21.4 | -8.6 | -32.2 | -8.6 |
| Net income attributable to noncontrolling interests, net | -0.9 | -1.4 | 2.4 | -2.8 | -1.4 | -1.7 | -7.7 | -1.2 |
| Net income attributable to Genie Energy Ltd. | 87.8 | 29.2 | 13.2 | 4.2 | 22.8 | -7.0 | -24.5 | -7.5 |
| Dividends on preferred stock | -1.9 | -1.7 | -1.5 | -1.5 | -1.5 | -1.5 | -1.5 | -1.5 |
| Net income attributable to Genie Energy Ltd. common stockholders | 85.9 | 27.5 | 11.7 | 2.7 | 21.3 | -8.5 | -26.0 | -8.9 |
| |
| Amounts attributable to Genie Energy Ltd. common stockholders | | | | | | | | |
| Net income attributable to Genie Energy Ltd. common stockholders | 85.9 | 27.5 | 11.7 | 2.7 | 21.3 | -8.5 | -26.0 | -8.9 |
| |
| Earnings per share attributed to Genie Energy Ltd. common stockholders | | | | | | | | |
| Basic: | | | | | | | | |
| Continuing operations | 0.0 | 0.0 | 0.0 | 0.0 | | | | |
| |
| Earnings per share attributable to Genie Energy Ltd. common stockholders | $3.35 | $1.06 | $0.45 | $0.10 | $0.85 | ($0.36) | ($1.14) | ($0.40) |
| |
| Diluted | | | | | | | | |
| Earnings per share attributable to Genie Energy Ltd. common stockholders | $3.26 | $1.05 | $0.44 | $0.10 | $0.83 | ($0.36) | ($1.14) | ($0.40) |
| |
| Weighted-average number of shares used in calculation of earnings per share: | | | | | | | | |
| Basic | 25.6 | 25.9 | 26.1 | 26.6 | 25.2 | 23.5 | 22.8 | 22.1 |
| Diluted | 26.4 | 26.3 | 26.8 | 27.5 | 25.7 | 23.5 | 22.8 | 22.1 |
| |
| Dividends declared per common share | $0.30 | | $0.33 | $0.30 | $0.30 | $0.30 | $0.24 | $0.12 |