Genie Energy (GNE) 10-K 16 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Mar. 13, 2018	Jun. 30, 2017
Entity Registrant Name	Genie Energy Ltd.
Entity Central Index Key	1,528,356
Trading Symbol	GNE
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 122
Class A common stock
Entity Common Stock, Shares Outstanding		1,574,326
Class B common stock
Entity Common Stock, Shares Outstanding		23,294,886

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
CURRENT ASSETS:
Cash and cash equivalents	$ 29,913	$ 35,192
Restricted cash - short-term	518	10,813
Trade accounts receivable, net of allowance for doubtful accounts of $1,099 and $171 at December 31, 2017 and 2016, respectively	44,629	36,858
Inventory	3,986	5,989
Prepaid expenses	6,131	4,026
Other current assets	4,985	4,932
TOTAL CURRENT ASSETS	90,162	97,810
Property and equipment, net	4,020	1,617
Goodwill	9,998	8,728
Other intangibles, net	4,859	4,277
Investment in joint venture	3,450
Restricted cash - long-term	1,496	1,047
Deferred income tax assets, net	2,141	1,781
Other assets	9,652	6,553
TOTAL ASSETS	125,778	121,813
CURRENT LIABILITIES:
Revolving line of credit		711
Trade accounts payable	21,068	17,274
Accrued expenses	28,069	16,301
Income taxes payable	2,204	2,426
Due to IDT Corporation	228	141
Other current liabilities	3,172	4,292
TOTAL CURRENT LIABILITIES	54,741	41,145
Revolving line of credit	2,513
Other liabilities	1,396	803
TOTAL LIABILITIES	58,650	41,948
Commitments and contingencies (Note 15 and Note 16)
Genie Energy Ltd. Stockholders' equity:
Preferred stock, $.01 par value; authorized shares - 10,000: Series 2012-A, designated shares - 8,750; at liquidation preference, consisting of 2,322 shares issued and outstanding at December 31, 2017 and 2016	19,743	19,743
Additional paid-in capital	130,870	128,243
Treasury stock, at cost, consisting of 331 and 201 shares of Class B common at December 31, 2017 and 2016, respectively	(2,428)	(1,599)
Accumulated other comprehensive income	3,045	1,465
Accumulated deficit	(67,469)	(51,567)
Total Genie Energy Ltd. stockholders' equity	84,013	96,534
Noncontrolling interests:
Noncontrolling interests	(16,885)	(15,002)
Receivable for issuance of equity		(1,667)
Total noncontrolling interests	(16,885)	(16,669)
TOTAL EQUITY	67,128	79,865
TOTAL LIABILITIES AND EQUITY	125,778	121,813
Class A common stock
Genie Energy Ltd. Stockholders' equity:
Common stock, value	16	16
Noncontrolling interests:
TOTAL EQUITY	16	16
Class B common stock
Genie Energy Ltd. Stockholders' equity:
Common stock, value	236	233
Noncontrolling interests:
TOTAL EQUITY	$ 236	$ 233

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts, trade accounts receivable (in dollars)	$ 1,099	$ 171
Preferred stock, par value (In dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000	10,000
Series 2012-A Preferred Stock
Designated shares	8,750	8,750
Preferred stock, shares issued	2,322	2,322
Preferred stock, shares outstanding	2,322	2,322
Class A common stock
Common stock, par value (In dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	35,000	35,000
Common stock, shares issued	1,574	1,574
Common stock, shares outstanding	1,574	1,574
Class B common stock
Common stock, par value (In dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000	200,000
Common stock, shares issued	23,601	23,274
Common stock, shares outstanding	23,270	23,073
Treasury stock, shares	331	201

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUES:
Electricity		$ 222,171	$ 179,467	$ 170,283
Natural gas		40,098	31,031	40,757
Other		1,933	1,614	2,016
Total revenues		264,202	212,112	213,056
Cost of revenues		178,693	135,172	146,409
GROSS PROFIT		85,509	76,940	66,647
OPERATING EXPENSES, (GAINS) AND LOSSES:
Selling, general and administrative	[1]	80,122	61,569	66,011
Research and development			(269)	1,985
Exploration		4,879	6,088	6,583
Write-off of capitalized exploration costs		6,483	41,041
Other operating loss, net			64
Gain on consolidation of AMSO, LLC			(1,262)
Equity in the net loss of joint ventures		565	222	397
Loss from operations		(6,540)	(30,513)	(8,329)
Interest income		295	332	411
Interest expense		(310)	(19)	(10)
Other (expense) income, net		(367)	226	(183)
Loss before income taxes		(6,922)	(29,974)	(8,111)
Provision for income taxes		(1,726)	(2,218)	(525)
NET LOSS		(8,648)	(32,192)	(8,636)
Net loss attributable to noncontrolling interests		1,654	7,667	1,179
NET LOSS ATTRIBUTABLE TO GENIE ENERGY LTD.		(6,994)	(24,525)	(7,457)
Dividends on preferred stock		(1,481)	(1,481)	(1,481)
NET LOSS ATTRIBUTABLE TO GENIE ENERGY LTD. COMMON STOCKHOLDERS		$ (8,475)	$ (26,006)	$ (8,938)
Basic and diluted loss per share attributable to Genie Energy Ltd. common stockholders		$ (0.36)	$ (1.14)	$ (0.40)
Weighted-average number of shares used in calculation of basic and diluted loss per share		23,531	22,804	22,135
[1]	Stock-based compensation included in selling, general and administrative expenses

Consolidated Statements of Ope5

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statements of Operations [Abstract]
Stock-based compensation included in selling, general and administrative expenses	$ 5,213	$ 4,813	$ 5,229

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statements of Comprehensive (Loss) Income [Abstract]
NET LOSS	$ (8,648)	$ (32,192)	$ (8,636)
Other comprehensive income:
Foreign currency translation adjustments	917	1,349	142
COMPREHENSIVE LOSS	(7,731)	(30,843)	(8,494)
Comprehensive loss attributable to noncontrolling interests	2,317	7,629	1,181
COMPREHENSIVE LOSS ATTRIBUTABLE TO GENIE ENERGY LTD.	$ (5,414)	$ (23,214)	$ (7,313)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Class A common stock	Class B common stock	Preferred Stock	Additional Paid-In Capital	Treasury Stock	Accumulated Other Comprehensive Income	Accumulated Deficit	Noncontrolling Interests	Receivable for issuance of equity
Beginning Balance at Dec. 31, 2014	$ 119,343	$ 16	$ 232	$ 19,743	$ 114,322	$ (1,543)	$ 10	$ (7,759)	$ (4,678)	$ (1,000)
Beginning Balance, Shares at Dec. 31, 2014		1,574	23,178	2,322
Dividends on preferred stock	(1,481)							(1,481)
Dividends on common stock	(2,950)							(2,950)
Restricted Class B common stock purchased from employees	(27)					(27)
Stock-based compensation	5,095				5,095
Restricted stock issued to employees and directors
Restricted stock issued to employees and directors, Shares			36
Exercise of stock options	174				174
Exercise of stock options, Shares			25
Class B common stock issued for GRE deferred stock units
Exercise of GOGAS stock option	2,500				5,979				(979)	(2,500)
Collection of receivables for issuance of equity	1,912				79					1,833
Subsidiary equity grant reclassified to liability	(1,200)				(1,200)
Payment for option to purchase noncontrolling interests	(175)								(175)
Other comprehensive income	142						144		(2)
Net loss for the year ended	(8,636)							(7,457)	(1,179)
Ending Balance at Dec. 31, 2015	114,697	$ 16	$ 232	$ 19,743	124,449	(1,570)	154	(19,647)	(7,013)	(1,667)
Ending Balance, Shares at Dec. 31, 2015		1,574	23,239	2,322
Dividends on preferred stock	(1,481)							(1,481)
Dividends on common stock	(5,914)							(5,914)
Restricted Class B common stock purchased from employees	(29)					(29)
Stock-based compensation	4,122				4,122
Restricted stock issued to employees and directors	1		$ 1
Restricted stock issued to employees and directors, Shares			35
Class B common stock issued for GRE deferred stock units
Sale of equity of subsidiary	1,000				1,360				(360)
Subsidiary equity grant reclassified to liability	(1,688)				(1,688)
Other comprehensive income	1,349						1,311		38
Net loss for the year ended	(32,192)							(24,525)	(7,667)
Ending Balance at Dec. 31, 2016	79,865	$ 16	$ 233	$ 19,743	128,243	(1,599)	1,465	(51,567)	(15,002)	(1,667)
Ending Balance, Shares at Dec. 31, 2016		1,574	23,274	2,322
Dividends on preferred stock	(1,481)							(1,481)
Dividends on common stock	(7,427)							(7,427)
Restricted Class B common stock purchased from employees	(829)					(829)
Stock-based compensation	3,090				$ 3,090
Stock-based compensation, Shares			24
Exercise of stock options	108				$ 108
Exercise of stock options, Shares			16
Purchases of equity of subsidiary	(312)				(746)				434
Class B common stock issued for GRE deferred stock units	1,845
Class B common stock issued for GRE deferred stock units, Shares			287
Receivable for issuance of equity of subsidiary written-off					(1,667)					1,667
Other comprehensive income	917						1,580		(663)
Net loss for the year ended	(8,648)							(6,994)	(1,654)
Ending Balance at Dec. 31, 2017	$ 67,128	$ 16	$ 236	$ 19,743	$ 130,870	$ (2,428)	$ 3,045	$ (67,469)	$ (16,885)
Ending Balance, Shares at Dec. 31, 2017		1,574	23,601	2,322

Consolidated Statements of Equ8

Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Dividends on common stock	$ 0.30	$ 0.24	$ 0.12

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING ACTIVITIES
Net loss	$ (8,648)	$ (32,192)	$ (8,636)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	2,140	581	428
Deferred income taxes	(360)	(139)	(180)
Provision for doubtful accounts receivable	762	8	(29)
Stock-based compensation	5,213	4,813	5,229
Loss on disposal of property		25	156
Gain from repayment of revolving credit loan payable		(200)
Write-off of capitalized exploration costs	6,483	41,041
Gain on consolidation of AMSO, LLC		(1,262)
Equity in the net loss of joint ventures	565	222	397
Change in assets and liabilities, net of effect of acquisition:
Restricted cash	(93)	905	(1,062)
Trade accounts receivable	(8,024)	(6,030)	4,234
Inventory	2,003	5,737	(274)
Prepaid expenses	(2,027)	7,539	(5,615)
Other current assets and other assets	(3,703)	2,863	(2,346)
Trade accounts payable, accrued expenses and other current liabilities	15,110	(9,566)	4,341
Due to IDT Corporation	88	(298)	(104)
Income taxes payable	(222)	1,503	380
Net cash provided by (used in) operating activities	9,287	15,550	(3,081)
INVESTING ACTIVITIES
Capital expenditures	(3,292)	(586)	(324)
Investments in capitalized exploration costs - unproved oil and gas property	(5,531)	(12,884)	(26,969)
Proceeds from disposal of property		27
Cash acquired from consolidation of AMSO, LLC		702
Capital contribution to AMSO, LLC received from Total		3,000
Capital contributions to AMSO, LLC		(63)	(250)
Payment for acquisition, net of cash acquired	(4,180)	(8,700)
Repayment of notes receivable	445	50	50
Investment in joint venture	(3,970)
Purchases of certificates of deposit		(2,974)	(8,820)
Proceeds from maturities of certificates of deposit		11,900	4,688
Net cash used in investing activities	(16,528)	(9,528)	(31,625)
FINANCING ACTIVITIES
Dividends paid	(8,908)	(7,395)	(4,431)
Purchases of equity of subsidiary	(312)
Payment for acquisitions		(227)	(358)
Proceeds from revolving line of credit and loan payable	14,450	3,650	2,000
Repayment of revolving line of credit and loan payable	(12,655)	(6,690)
Decrease in restricted cash	10,000
Proceeds from exercise of stock options	108		174
Proceeds from sales of equity of subsidiaries		1,000	2,500
Collection of receivables for issuance of equity			1,912
Payment for option to purchase noncontrolling interests			(175)
Repurchases of Class B common stock	(829)	(29)	(27)
Net cash provided by (used in) financing activities	1,854	(9,691)	1,595
Effect of exchange rate changes on cash and cash equivalents	108	75	2
Net decrease in cash and cash equivalents	(5,279)	(3,594)	(33,109)
Cash and cash equivalents at beginning of period	35,192	38,786	71,895
Cash and cash equivalents at end of period	29,913	35,192	38,786
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash payments made for interest	310	19	10
Cash payments made for income taxes	2	745	49
SUPPLEMENTAL SCHEDULE OF NON-CASH FINANCING AND INVESTING ACTIVITIES
Class B common stock issued for GRE deferred stock units	1,845
Receivable for issuance of equity written-off	1,667
Subsidiary equity grant reclassified to liability		1,688	1,200
Liability incurred for acquisition		312
Receivables for issuance of equity of subsidiaries			$ 2,500

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Description of Business and Summary of Significant Accounting Policies [Abstract]
Description of Business and Summary of Significant Accounting Policies	Note 1 — Description of Business and Summary of Significant Accounting Policies Description of Business Genie Energy Ltd. (“Genie”), a Delaware corporation, was incorporated in January 2011. Genie owns 99.3% of its subsidiary, Genie Energy International Corporation (“GEIC”), which owns 100% of Genie Retail Energy (“GRE”) and 92% of Genie Oil and Gas, Inc. (“GOGAS”). The “Company” in these financial statements refers to Genie, Genie Retail Energy and Genie Oil and Gas, and their respective subsidiaries, on a consolidated basis. Genie 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 in the Eastern and Midwestern United States. Genie is also comprised of Genie Oil and Gas, 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, whose operations have been suspended. GOGAS also holds controlling interests in other inactive oil and gas projects. GRE has outstanding deferred stock units granted to officers and employees that represent an interest of 1.25% of the equity of GRE. Basis of Consolidation The method of accounting applied to long-term investments, whether consolidated, equity or cost, involves an evaluation of the significant terms of each investment that explicitly grant or suggest evidence of control or influence over the operations of the investee and also includes the identification of any variable interests in which the Company is the primary beneficiary. The consolidated financial statements include the Company’s controlled subsidiaries and the variable interest entity in which the Company is the primary beneficiary (see Note 13). All significant intercompany accounts and transactions between the consolidated entities are eliminated. Accounting for Investments Investments in businesses that the Company does not control, but in which the Company has the ability to exercise significant influence over operating and financial matters, are accounted for using the equity method. The Company periodically evaluates its equity method investments for impairment due to declines considered to be other than temporary. If the Company determines that a decline in fair value is other than temporary, then a charge to earnings is recorded, and a new basis in the investment is established. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates. Revenue Recognition Revenues from GRE’s sale of electricity and natural gas are recognized under the accrual method based on deliveries of electricity and natural gas to customers. Revenues from electricity and natural gas delivered but not billed are estimated and recorded as accounts receivable. Cash received in advance from customers under billing arrangement is reported as deferred revenue and is included in “Accrued expenses” in the accompanying consolidated balance sheets. GOGAS does not yet generate revenues. In May 2014, the Financial Accounting Standards Board (“FASB”) and the International Accounting Standards Board jointly issued a comprehensive new revenue recognition standard that superseded most of the revenue recognition guidance under U.S. GAAP and International Financial Reporting Standards (“IFRS”). The goals of the revenue recognition project were to clarify and converge the revenue recognition principles under U.S. GAAP and IFRS and to develop guidance that would streamline and enhance revenue recognition requirements. The Company adopted this standard on January 1, 2018 using the modified retrospective method. The Company has substantially completed its evaluation of the effects of adopting the new standard and determined that it will not have any impact on revenue recognition and measurement in its consolidated financial statements upon adoption. Variable quantities in requirements contracts are considered to be options for additional goods and services which follow discussions outlined in the AICPA Power and Utilities Industry Task Force Issue No. 13-2. Revenue for each unit of electricity or natural gas is recognized as it is delivered to the customer. The Company will estimate variable consideration related to its rebate programs using the expected value method and a portfolio approach. The Company expects to apply a practical expedient for expensing costs to obtain a contract as the estimated customer relationship periods are currently less than twelve months. The Company will monitor its customer relationship periods going forward to ensure compliance with the application of the practical expedient. The adoption of the new standard will not have any impact on the Company’s current method of recording accrued rebates. The Company is also currently reviewing future required disclosures, and updating its accounting policy. The Company anticipates completing the implementation in connection with its first quarter 2018 interim financial statements. Cost of Revenues Cost of revenues for GRE consists primarily of the cost of natural gas and electricity sold, and also includes financing fees, scheduling costs, Independent System Operator (“ISO”) fees, pipeline costs and utility service charges. In addition, the changes in the fair value of GRE’s futures contracts, swaps and put and call options are recorded in cost of revenues. GOGAS does not yet incur cost of revenues. Research and Development Costs Research and development costs are charged to expense as incurred. Oil and Gas Exploration Costs The Company accounts for its oil and gas activities under the successful efforts method of accounting. Under this method, the costs of drilling exploratory wells and exploratory-type stratigraphic test wells are capitalized, pending determination of whether the well has found proved reserves. Other exploration costs are charged to expense as incurred. Unproved properties are assessed for impairment, and if considered impaired, are charged to expense when such impairment is deemed to have occurred (see Note 5). Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents. Inventory Inventory consists of natural gas, which is stored at various third parties’ underground storage facilities, of $1.0 million and $0.6 million at December 31, 2017 and 2016, respectively. Inventory also includes renewable energy credits of $3.0 million and $5.4 million at December 31, 2017 and 2016, respectively. On January 1, 2017, the Company adopted the Accounting Standards Update (“ASU”) that changed the measurement of its natural gas inventory to the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. The adoption of this ASU did not have a significant impact on the Company’s consolidated financial statements. Prior to January 1, 2017, the Company’s natural gas inventory was valued at weighted average cost, which was based on the purchase price of the natural gas and the cost to transport, plus or minus injections or withdrawals. Renewable Energy Credits GRE must obtain a certain percentage or amount of its power supply from renewable energy sources in order to meet the requirements of renewable portfolio standards in the states in which it operates. This requirement may be met by obtaining renewable energy credits that provide evidence that electricity has been generated by a qualifying renewable facility or resource. GRE holds renewable energy credits for both sale and use, and treats the credits as a government incentive to encourage the construction of renewable power plants. Renewable energy credits are valued at the lower of cost and market, where cost is the purchase price. Gains and losses from the sale of renewable energy credits are recognized in cost of revenues when the credits are transferred to the buyer. Long-Lived Assets Computer software and development, computers and computer hardware, laboratory and drilling equipment and office equipment and other are recorded at cost and are depreciated on a straight-line basis over their estimated useful lives, which range as follows: computer software and development — 2, 3 or 5 years; computers and computer hardware — 5 years, laboratory and drilling equipment — 7 years, and office equipment and other —5 or 7 years. Leasehold improvements included in office equipment and other are recorded at cost and are depreciated on a straight-line basis over the term of their lease or their estimated useful lives, whichever is shorter. The fair value of patents and trademarks, non-compete agreements and customer relationships acquired in a business combination accounted for under the purchase method are amortized over their estimated useful lives as follows: patents and trademarks are amortized on a straight-line basis over the 20-year period of expected cash flows; non-compete agreements are amortized on a straight-line basis over their 2 year term; and customer relationships are amortized ratably over the 2 or 9 year period of expected cash flows. The Company tests the recoverability of its long-lived assets with finite useful lives whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The Company tests the recoverability based on the projected undiscounted cash flows to be derived from such asset. If the projected undiscounted future cash flows are less than the carrying value of the asset, the Company will record an impairment loss based on the difference between the estimated fair value and the carrying value of the asset. The Company generally measures fair value by considering sale prices for similar assets or by discounting estimated future cash flows from such asset using an appropriate discount rate. Cash flow projections and fair value estimates require significant estimates and assumptions by management. Should the estimates and assumptions prove to be incorrect, the Company may be required to record impairments in future periods and such impairments could be material. Goodwill and Indefinite Lived Intangible Assets Goodwill is the excess of the acquisition cost of businesses over the fair value of the identifiable net assets acquired. Goodwill and other indefinite lived intangible assets are not amortized. These assets are reviewed annually (or more frequently under various conditions) for impairment using a fair value approach. In 2017, the Company adopted the ASU that simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. In computing the implied fair value of goodwill under Step 2, an entity had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities (including unrecognized assets and liabilities) following the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Instead, under the amendments in this ASU, the Company performs its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. The Company would recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized would not exceed the total amount of goodwill allocated to that reporting unit. Additionally, the Company considers income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The fair value of the reporting unit is estimated using discounted cash flow methodologies, as well as considering third party market value indicators. Calculating the fair value of the reporting units requires significant estimates and assumptions by management. Should the estimates and assumptions regarding the fair value of the reporting units prove to be incorrect, the Company may be required to record impairments to its goodwill in future periods and such impairments could be material. The Company has the option to perform a qualitative assessment to determine whether it is necessary to perform the quantitative goodwill impairment test. However, the Company may elect to perform the quantitative goodwill impairment test even if no indications of a potential impairment exist. For the impairment test of the Company’s indefinite-lived intangible assets, a quantitative impairment test is only necessary if the Company determines that it is more likely than not that an indefinite-lived intangible asset is impaired based on an assessment of certain qualitative factors. Derivative Instruments and Hedging Activities The Company records its derivatives instruments at their respective fair values. The accounting for changes in the fair value (that is, gains or losses) of a derivative instrument is dependent upon whether the derivative has been designated and qualifies as part of a hedging relationship and further, on the type of hedging relationship. Due to the volatility of electricity and natural gas prices, GRE enters into futures contracts, swaps and put and call options as hedges against unfavorable fluctuations in market prices of electricity and natural gas and to reduce exposure from price fluctuations. The Company does not designate its derivative instruments to qualify for hedge accounting, accordingly the futures contracts, swaps and put and call options are recorded at fair value as a current asset or liability and any changes in fair value are recorded in “Cost of revenues” in the consolidated statements of operations. In addition to the above, GRE utilizes forward physical delivery contracts for a portion of its purchases of electricity and natural gas, which are defined as commodity derivative contracts. Using the exemption available for qualifying contracts, GRE applies the normal purchase and normal sale accounting treatment to its forward physical delivery contracts, thereby these contracts are not adjusted to fair value. GRE also applies the normal purchase and normal sale accounting treatment to forward contracts for the physical delivery of electricity in nodal energy markets that result in locational marginal pricing charges or credits, since this does not constitute a net settlement, even when legal title to the electricity is conveyed to the ISO during transmission. Accordingly, GRE recognizes revenue from customer sales, and the related cost of revenues, at the contracted price, as electricity and natural gas is delivered to retail customers. Repairs and Maintenance The Company charges the cost of repairs and maintenance, including the cost of replacing minor items not constituting substantial betterment, to selling, general and administrative expense as these costs are incurred. Foreign Currency Translation Assets and liabilities of foreign subsidiaries denominated in foreign currencies are translated to U.S. Dollars at end-of-period rates of exchange, and their monthly results of operations are translated to U.S. Dollars at the average rates of exchange for that month. Gains or losses resulting from such foreign currency translations are recorded in “Accumulated other comprehensive income” in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are reported in “Other (expense) income, net” in the accompanying consolidated statements of operations. Advertising Expense Cost of advertising for customer acquisitions are charged to selling, general and administrative expense in the period in which it is incurred. Most of the advertisements are in print, over the radio, or direct mail. In the years ended December 31, 2017, 2016 and 2015, advertising expense included in selling, general and administrative expense was $2.1 million, $1.4 million and $0.9 million, respectively. Income Taxes The Company recognizes deferred tax assets and liabilities for the future tax consequences attributable to temporary differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The ultimate realization of deferred tax assets depends on the generation of future taxable income during the period in which related temporary differences become deductible. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in its assessment of a valuation allowance. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date of such change. The Company uses a two-step approach for recognizing and measuring tax benefits taken or expected to be taken in a tax return. The Company determines whether it is more-likely-than-not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Company presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. Tax positions that meet the more-likely-than-not recognition threshold are measured to determine the amount of tax benefit to recognize in the financial statements. The tax position is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon ultimate settlement. Differences between tax positions taken in a tax return and amounts recognized in the financial statements will generally result in one or more of the following: an increase in a liability for income taxes payable, a reduction of an income tax refund receivable, a reduction in a deferred tax asset, or an increase in a deferred tax liability. The Company classifies interest and penalties on income taxes as a component of income tax expense. Contingencies The Company accrues for loss contingencies when both (a) information available prior to issuance of the financial statements indicates that it is probable that a liability had been incurred at the date of the financial statements and (b) the amount of loss can reasonably be estimated. When the Company accrues for loss contingencies and the reasonable estimate of the loss is within a range, the Company records its best estimate within the range. When no amount within the range is a better estimate than any other amount, the Company accrues the minimum amount in the range. The Company discloses an estimated possible loss or a range of loss when it is at least reasonably possible that a loss may have been incurred. Earnings Per Share Basic earnings per share is computed by dividing net income or loss attributable to all classes of common stockholders of the Company by the weighted average number of shares of all classes of common stock outstanding during the applicable period. Diluted earnings per share is determined in the same manner as basic earnings per share, except that the number of shares is increased to include restricted stock still subject to risk of forfeiture and to assume exercise of potentially dilutive stock options using the treasury stock method, unless the effect of such increase is anti-dilutive. The following shares were excluded from the diluted earnings per share computations because their inclusion would have been anti-dilutive: Year ended December 31, (in thousands) 2017 2016 2015 Stock options 383 414 414 Non-vested restricted Class B common stock 762 1,226 1,852 Shares excluded from the calculation of diluted earnings per share 1,145 1,640 2,266 The diluted loss per share equals basic loss per share in the years ended December 31, 2017, 2016 and 2015 because the Company had a net loss and the impact of the assumed exercise of stock options and vesting of restricted stock would have been anti-dilutive. In March 2018, the Company and an entity affiliated with Lord (Jacob) Rothschild agreed in principle that the Rothschild’s entity will exercise its option to exchange its 5% equity interest in GOGAS for Class B shares of the Company’s common stock with a fair value of $0.2 million. Employees and directors of the Company that were previously granted restricted stock of Afek and Genie Mongolia, Inc. (“Genie Mongolia”) have the right to exchange the restricted stock, upon vesting of such shares, into shares of the Company’s Class B common stock. GRE has the right, at its option, to satisfy its obligations to issue common stock of GRE upon the vesting of the deferred stock units it granted in July 2015 to officers and employees of the Company in shares of the Company’s Class B common stock or cash. These exchanges and issuances, if elected, would be based on the relative fair value of the shares exchanged or to be issued. The number of shares of the Company’s stock issuable in an exchange is not currently determinable. If shares of the Company’s stock are issued upon such exchange, the Company’s earnings per share may be diluted in future periods. Stock-Based Compensation The Company recognizes compensation expense for grants of stock-based awards to its employees based on the estimated fair value on the grant date. Stock based awards granted to nonemployees are marked-to-market until the vesting of the award. Compensation cost for awards is recognized using the straight-line method over the requisite service period, which approximates the vesting period. Stock-based compensation is included in selling, general and administrative expense. Vulnerability Due to Certain Concentrations Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash, cash equivalents, restricted cash, certificates of deposit and trade accounts receivable. The Company holds cash, cash equivalents, restricted cash and certificates of deposit at several major financial institutions, which may exceed FDIC insured limits. Historically, the Company has not experienced any losses due to such concentration of credit risk. The Company’s temporary cash investments policy is to limit the dollar amount of investments with any one financial institution and monitor the credit ratings of those institutions. While the Company may be exposed to credit losses due to the nonperformance of the holders of its deposits, the Company does not expect the settlement of these transactions to have a material effect on its results of operations, cash flows or financial condition. GRE’s REPs reduce their customer credit risk by participating in purchase of receivable programs for a majority of their receivables. In addition to providing billing and collection services, utility companies purchase those REPs’ receivables and assume all credit risk without recourse to those REPs. GRE’s REPs’ primary credit risk is therefore nonpayment by the utility companies. Certain of the utility companies represent significant portions of the Company’s consolidated revenues and consolidated gross trade accounts receivable balance and such concentrations increase the Company’s risk associated with nonpayment by those utility companies. The following table summarizes the percentage of consolidated revenues from customers by utility company that equal or exceed 10% of consolidated revenues in the period (no other single utility company accounted for more than 10% of consolidated revenues in these periods): Year ended December 31, 2017 2016 2015 Con Edison 15 % 20 % 23 % ComEd 10 % 13 % na National Grid USA na na 12 % na – less than 10% of consolidated revenue in the period The following table summarizes the percentage of consolidated gross trade accounts receivable by utility company that equal or exceed 10% of consolidated gross trade accounts receivable at December 31, 2017 and 2016 (no other single utility company accounted for 10% or greater of the Company’s consolidated gross trade accounts receivable at December 31, 2017 or 2016): December 31 2017 2016 Con Edison 11 % 15 % ComEd na 10 % na – less than 10% of consolidated gross trade accounts receivable Allowance for Doubtful Accounts The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the accounts receivable balance. The allowance is determined based on known troubled accounts, historical experience and other currently available evidence. Doubtful accounts are written-off upon final determination that the trade accounts will not be collected. The change in the allowance for doubtful accounts was as follows: (in thousands) Balance at beginning of period Additions charged (reversals credited) to expense Additions (deductions) (1) Balance at end of period Year ended December 31, 2017 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 171 $ 762 $ 166 $ 1,099 Year ended December 31, 2016 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 182 $ 8 $ (19 ) $ 171 Year ended December 31, 2015 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 227 $ (29 ) $ (16 ) $ 182 (1) Primarily uncollectible accounts written off, net of recoveries. Fair Value Measurements Fair value of financial and non-financial assets and liabilities is defined as an exit price, which is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three-tier hierarchy for inputs used to measure fair value, which prioritizes the inputs to valuation techniques used to measure fair value, is as follows: Level 1 — quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 — quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 — unobservable inputs based on the Company’s assumptions used to measure assets and liabilities at fair value. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of the assets and liabilities being measured and their placement within the fair value hierarchy. Accounting Standards Updates In January 2016, the FASB issued an ASU to provide more information about recognition, measurement, presentation and disclosure of financial instruments. The amendments in the ASU include, among other changes, the following: (1) equity investments (except those accounted for under the equity method or that result in consolidation) will be measured at fair value with changes in fair value recognized in net income, (2) a qualitative assessment each reporting period to identify impairment of equity investments without readily determinable fair values, (3) financial assets and financial liabilities will be presented separately by measurement category and form of financial asset on the balance sheet or the notes to the financial statements, and (4) an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. Entities will no longer be able to recognize unrealized holding gains and losses on equity securities classified as available-for-sale in other comprehensive income. In addition, a practicability exception will be available for equity investments that do not have readily determinable fair values and do not qualify for the net asset value practical expedient. These investments may be measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer. Entities will have to reassess at each reporting period whether an investment qualifies for this practicability exception. The Company adopted the amendments in this ASU on January 1, 2018. This ASU did not have a significant impact on the Company’s consolidated financial statements. In February 2016, the FASB issued an ASU related to the accounting for leases. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The Company will adopt the new standard on January 1, 2019. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is evaluating the impact that the new standard will have on its consolidated financial statements. In June 2016, the FASB issued an ASU that changes the impairment model for most financial assets and certain other instruments. For receivables, loans and other instruments, entities will be required to use a new forward-looking “expected loss” model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities will measure credit losses in a manner similar to current practice, except the losses will be recognized as allowances instead of reductions in the amortized cost of the securities. In addition, an entity will have to disclose significantly more information about allowances, credit quality indicators and past due securities. The new provisions will be applied as a cumulative-effect adjustment to retained earnings. The Company will adopt the new standard on January 1, 2020. The Company is evaluating the impact that the new standard will have on its consolidated financial statements. In November 2016, the FASB issued an ASU that includes specific guidance on the classification and presentation of changes in restricted cash and cash equivalents in the statement of cash flows. The amendments in this ASU require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Amounts generally described as restricted cash or restricted cash equivalents will be included with cash and cash equivalents when reconciling the beginning of the period and end of the period total amounts shown on the statement of cash flows. The ASU will be applied using a retrospective transition method to each period presented. The Company adopted the amendments in this ASU on January 1, 2018. Beginning in the first quarter of 2018, the adoption will impact the Company’s beginning of the period and end of the period cash and cash equivalents balance in its statement of cash flows, as well as its net cash provided by operating and financing activities. In January 2017, the FASB issued an ASU to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. Under the current guidance, there are three elements of a business—inputs, pro

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Acquisitions [Abstract]
Acquisitions	Note 2 — Acquisitions Acquisition of Retail Energy Holdings, LLC On November 2, 2016, GRE acquired Retail Energy Holdings, LLC (“REH”), a privately held owner of REPs, for $9.5 million plus $1.4 million for REH’s working capital, or an aggregate cash payment of $10.9 million. REH operates as Town Square Energy in eight states. REH’s licenses and customer base expanded GRE’s geographic footprint to four new states – New Hampshire, Rhode Island, Massachusetts and Connecticut – and provided additional electricity customers in New Jersey, Maryland, Ohio and Pennsylvania. REH operates as a wholly owned subsidiary utilizing the Town Square Energy brand. REH’s operating results from the date of acquisition, which were not significant, are included in the Company’s consolidated financial statements. The impact of the acquisition’s purchase price allocations on the Company’s consolidated balance sheet and the acquisition date fair value of the total consideration transferred were as follows: (in thousands) Trade accounts receivable $ 3,614 Inventory 287 Prepaid expenses 81 Other current assets 26 Property and equipment 110 Trademark 2,100 Non-compete agreement 110 Customer relationships (2-year useful life) 2,100 Goodwill 5,065 Other assets 1,600 Revolving line of credit (1,919 ) Trade accounts payable (2,620 ) Accrued expenses (1,542 ) Net assets excluding cash acquired $ 9,012 Supplemental information: Cash paid $ 10,949 Cash acquired (2,249 ) Cash paid, net of cash acquired 8,700 Liability for additional purchase price (paid in 2017) 312 Total consideration, net of cash acquired $ 9,012 The goodwill resulting from the acquisition is primarily attributable to the existing workforce of the acquired entities and synergies from the combination of GRE and REH’s REP businesses. None of the goodwill is deductible for income tax purposes. The following table presents unaudited pro forma information of the Company as if the acquisition occurred on January 1, 2015: Year ended December 31, (in thousands) 2016 2015 Revenues $ 243,147 $ 243,165 Net loss $ (32,303 ) $ (11,256 ) Acquisition of Mirabito Natural Gas On August 10, 2017, GRE acquired Mirabito Natural Gas, a Ft. Lauderdale, Florida-based natural gas supplier, from Angus Partners, LLC (“Angus”) for an aggregate cash payment of $4.0 million. Mirabito serves commercial and government customers throughout Florida. Mirabito’s operating results from the date of acquisition, which were not significant, are included in the Company’s consolidated financial statements. Also on August 10, 2017, GRE and Angus entered into a Management Agreement pursuant to which Angus will provide any and all functions required to run and operate Mirabito. The Management Agreement terminates in August 2021, unless otherwise terminated by GRE for failure to achieve the business profit thresholds contained in the Management Agreement. Angus will receive an annual management fee from GRE equal to the greater of 30% of the business profits of Mirabito, as defined, or $250,000. The impact of the acquisition’s purchase price allocations on the Company’s consolidated balance sheet and the acquisition date fair value of the total consideration transferred were as follows: (in thousands) Trade accounts receivable $ 509 Prepaid expenses 60 Non-compete agreement 5 Customer relationships (9-year useful life) 1,100 Patents and trademarks 760 Goodwill 1,270 Other assets 465 Trade accounts payable (299 ) Accrued expenses (2 ) Net assets excluding cash acquired $ 3,868 Supplemental information: Cash paid $ 3,955 Cash acquired (87 ) Total consideration, net of cash acquired $ 3,868 The goodwill resulting from the acquisition is primarily attributable to the existing workforce of the acquired entities and synergies expected from the combination of GRE and Mirabito’s REP businesses. This goodwill is deductible for income tax purposes. The following table presents unaudited pro forma information of the Company as if the acquisition occurred on January 1, 2016: Year ended December 31, (in thousands) 2017 2016 Revenues $ 268,008 $ 217,448 Net loss $ (8,588 ) $ (32,031 )

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Measurements [Abstract]
Fair Value Measurements	Note 3 — Fair Value Measurements The following table presents the balance of assets and liabilities measured at fair value on a recurring basis: (in thousands) Level 1 (1) Level 2 (2) Level 3 (3) Total December 31, 2017 Assets: Derivative contracts $ 3,091 $ 1,267 $ — $ 4,358 Liabilities: Derivative contracts $ 693 $ 535 $ — $ 1,228 December 31, 2016 Assets: Derivative contracts $ 256 $ 2,395 $ — $ 2,651 Liabilities: Derivative contracts $ 60 $ 1,667 $ — $ 1,727 (1) quoted prices in active markets for identical assets or liabilities (2) observable inputs other than quoted prices in active markets for identical assets and liabilities (3) no observable pricing inputs in the market The Company’s derivative contracts consist of natural gas and electricity put and call options and swaps. The underlying asset in the Company’s put and call options is a forward contract. The Company’s swaps are agreements whereby a floating (or market or spot) price is exchanged for a fixed price over a specified period. Fair Value of Other Financial Instruments The estimated fair value of the Company’s other financial instruments was determined using available market information or other appropriate valuation methodologies. However, considerable judgment is required in interpreting this data to develop estimates of fair value. Consequently, the estimates are not necessarily indicative of the amounts that could be realized or would be paid in a current market exchange. Restricted cash — short-term and long-term, prepaid expenses, other current assets, revolving line of credit—current, due to IDT Corporation and other current liabilities. —current Other assets, revolving line of credit—long-term and other liabilities. —long-term

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2017
Derivative Instruments [Abstract]
Derivative Instruments	Note 4 — Derivative Instruments The primary risk managed by the Company using derivative instruments is commodity price risk, which is accounted for in accordance with Accounting Standards Codification 815 — Derivatives and Hedging. Natural gas and electricity put and call options and swaps are entered into as hedges against unfavorable fluctuations in market prices of natural gas and electricity. The Company does not apply hedge accounting to these options or swaps, therefore the changes in fair value are recorded in earnings. By using derivative instruments to mitigate exposures to changes in commodity prices, the Company exposes itself to credit risk and market risk. Credit risk is the failure of the counterparty to perform under the terms of the derivative contract. When the fair value of a derivative contract is positive, the counterparty owes the Company, which creates credit risk. The Company minimizes the credit or repayment risk in derivative instruments by entering into transactions with high-quality counterparties. At December 31, 2017 and 2016, GRE’s swaps and options were traded on the New York Mercantile Exchange. The summarized volume of GRE’s outstanding contracts and options at December 31, 2017 was as follows (MWh – Megawatt hour and Dth – Decatherm): Commodity Settlement Dates Volume Electricity First quarter 2018 739,120 MWh Electricity Third quarter 2018 339,440 MWh Electricity Fourth quarter 2018 209,920 MWh Natural gas First quarter 2018 2,873,215 Dth Natural gas Second quarter 2018 306,725 Dth Natural gas Third quarter 2018 57,125 Dth Natural gas Fourth quarter 2018 66,030 Dth Natural gas First quarter 2019 61,350 Dth Natural gas Second quarter 2019 35,100 Dth Natural gas Third quarter 2019 19,050 Dth The fair value of outstanding derivative instruments recorded in the accompanying consolidated balance sheets were as follows: December 31 (in thousands) 2017 2016 Asset Derivatives Balance Sheet Location Derivatives not designated or not qualifying as hedging instruments: Energy contracts and options Other current assets $ 4,358 $ 2,651 Liability Derivatives Derivatives not designated or not qualifying as hedging instruments: Energy contracts and options Other current liabilities $ 1,228 $ 1,727 The effects of derivative instruments on the consolidated statements of operations were as follows: Amount of Gain (Loss) Year ended December 31, (in thousands) 2017 2016 2015 Derivatives not designated or not qualifying as hedging instruments Location of Loss Recognized on Derivatives Energy contracts and options Cost of revenues $ (1,291 ) $ (538 ) $ (1,772 )

Afek Oil and Gas Exploration Ac

Afek Oil and Gas Exploration Activities	12 Months Ended
	Dec. 31, 2017
Afek Oil and Gas Exploration Activities [Abstract]
Afek Oil and Gas Exploration Activities	Note 5 — Afek Oil and Gas Exploration Activities In April 2013, the Government of Israel finalized the award to Afek of an exclusive three-year petroleum exploration license covering 396.5 square kilometers in the southern portion of the Golan Heights in Northern Israel. The license has been extended to April 2018. Israel’s Northern District Planning and Building Committee granted Afek a one-year permit that commenced in February 2015, which has been subsequently extended to April 18, 2018, to conduct an up to ten-well oil and gas exploration program. In February 2015, Afek began drilling its first exploratory well. Afek completed drilling five wells in the Southern region of its license area. In light of the analysis received in the third quarter of 2016 and the information and market conditions at that time, Afek determined that it did not have a clear path to demonstrate probable or possible reserves in the Southern region of its license area over the next 12 to 18 months. Since there was substantial doubt regarding the economic viability of these wells, in the year ended December 31, 2016, Afek wrote off the $41.0 million of capitalized exploration costs incurred in the Southern region. In 2017, Afek turned its operational focus to the Northern region of its license area. Afek viewed the Northern and Southern regions separately when evaluating its unproved properties. In 2017, Afek commenced drilling its sixth exploratory well at a site in the Northern portion of its license area. In November 2017, Afek announced that the preliminary analysis of results from the completed well at the Northern site suggested that the well’s target zone does not contain commercially producible quantities of oil or natural gas, and that it was suspending drilling operations pending further analysis. In the fourth quarter of 2017, Afek determined that it did not have a clear path to demonstrate probable or possible reserves in the Northern region of its license area over the next 12 to 18 months. Since there was substantial doubt regarding the economic viability of the well, Afek wrote off the $6.5 million of capitalized exploration costs incurred in the Northern region.

Investment in Joint Ventures

Investment in Joint Ventures	12 Months Ended
	Dec. 31, 2017
Investment in Joint Ventures [Abstract]
Investment in Joint Ventures	Note 6 — Investment in Joint Ventures Investment in American Shale Oil, LLC The Company, through GOGAS, has a 98.3% interest in American Shale Oil Corporation (“AMSO”), which operated American Shale Oil, L.L.C. (“AMSO, LLC”), its oil shale development project in Colorado. Through April 30, 2016, the Company accounted for its ownership interest in AMSO, LLC using the equity method since the Company had the ability to exercise significant influence over its operating and financial matters, although it did not control AMSO, LLC. AMSO, LLC was a variable interest entity, however, the Company determined that it was not the primary beneficiary, as the Company did not have the power to direct the activities of AMSO, LLC that most significantly impact AMSO, LLC’s economic performance. On February 23, 2016, TOTAL S.A. (“Total”) notified the Company of its decision not to continue to fund AMSO, LLC. On March 23, 2016, Total gave AMSO its notice of withdrawal from AMSO, LLC. The withdrawal was effective on April 30, 2016. As of April 1, 2016, AMSO and Total agreed that Total would pay AMSO, LLC $3.0 million as full payment of its share of all costs associated with the decommissioning, winding up and dissolution of AMSO, LLC. Total will not be refunded any amount if the decommissioning costs are less than $3.0 million. At December 31, 2016, the AMSO, LLC project was substantially decommissioned. Effective April 30, 2016, AMSO, LLC’s assets, liabilities, results of operations and cash flows are included in the Company’s consolidated financial statements. The following table summarizes the change in the balance of the Company’s investment in AMSO, LLC: Year ended December 31, (in thousands) 2017 2016 2015 Balance, beginning of period $ — $ (399 ) $ (252 ) Capital contributions — 63 250 Equity in net loss of AMSO, LLC — (222 ) (397 ) Elimination of the investment in AMSO, LLC — 558 — Balance, end of period $ — $ — $ (399 ) Summarized statements of operations of AMSO, LLC through the April 30, 2016 acquisition date were as follows: (in thousands) Period from January 1, 2016 to April 30, 2016 Year ended December 31, 2015 REVENUES $ — $ — OPERATING EXPENSES: General and administrative 120 403 Research and development 3,512 4,782 TOTAL OPERATING EXPENSES 3,632 5,185 Loss from operations (3,632 ) (5,185 ) Other income — — NET LOSS $ (3,632 ) $ (5,185 ) Summarized balance sheet of AMSO, LLC at April 30, 2016 (in thousands) was as follows: Assets Cash and cash equivalents $ 750 Receivable from Total 3,000 Other current assets 128 Other assets 860 Total assets $ 4,738 Liabilities and member’s interest Current liabilities $ 518 Asset retirement obligations 2,535 Other liabilities 981 Member’s interest 704 Total liabilities and member’s interest $ 4,738 The Company accounted for its acquisition on April 30, 2016 of Total’s ownership interest in AMSO, LLC as a business combination. The Company estimated the fair value of AMSO, LLC to be nil, as it had ceased operations and its shutdown was in progress. The Company recognized a gain from the acquisition of Total’s interest in AMSO, LLC because the Company acquired the net assets of AMSO, LLC while no consideration was transferred by the Company, due to the Company’s assumption of the risk associated with the shutdown obligations. The gain also included the Company’s gain on the remeasurement of AMSO’s investment in AMSO, LLC at its acquisition date fair value. The aggregate gain recognized was $1.3 million, which was included in “Gain on consolidation of AMSO, LLC” in the consolidated statements of operations. Revenue, income from operations and net income of AMSO, LLC since the acquisition date included in the Company’s consolidated statement of operations are as follows: (in thousands) Year ended December 31, 2016 Revenues $ — Income from operations $ 118 Net income $ 76 The following table presents unaudited pro forma information of the Company as if the acquisition occurred on January 1, 2015: Year ended December 31, (in thousands) 2016 2015 Revenues $ 212,112 $ 213,056 Net loss $ (35,602 ) $ (13,424 ) In April 2016, AMSO, LLC recorded a liability for the decommissioning of its project and the remediation of the leased area. The following table summarizes the change in the balance of the AMSO, LLC retirement obligations after the consolidation of AMSO, LLC: (in thousands) Year ended December 31, 2017 Period from April 30, 2016 to December 31, 2016 Balance, beginning of period $ 116 $ 2,535 Adjustments (60 ) (441 ) Payments (56 ) (1,978 ) Balance, end of period $ — $ 116 Investment in Shoreditch Energy Limited On July 17, 2017, the Company’s subsidiary, Genie Energy UK Ltd. (“GEUK”), entered into a definitive agreement with Energy Global Investments Pty Ltd (“EGC”) to launch Shoreditch Energy Limited (“Shoreditch”), a joint venture to offer electricity and natural gas service to residential and small business customers in the United Kingdom. At December 31, 2017, GEUK had contributed $4.0 million to Shoreditch, and GEUK will contribute an additional aggregate of up to £2.2 million ($3.0 million at December 31, 2017) by August 1, 2018, contingent on Shoreditch’s achievement of performance based milestones. EGC is obligated to contribute an aggregate of up to £1.7 million ($2.2 million at December 31, 2017) to Shoreditch by August 1, 2018, contingent on Shoreditch’s achievement of performance based milestones. GEUK owns 65% of the equity of Shoreditch and EGC owns 35% of the equity. GEUK appoints three members and EGC appoints two members to Shoreditch’s Board of Directors. EGC has several significant participating rights in the management of Shoreditch that limits GEUK’s ability to direct the activities that most significantly impact Shoreditch’s economic performance. GEUK therefore accounts for its ownership interest in Shoreditch using the equity method since GEUK has the ability to exercise significant influence over its operating and financial matters, although it does not control Shoreditch. Shoreditch is a variable interest entity, however, the Company has determined that it is not the primary beneficiary, as the Company does not have the power to direct the activities of Shoreditch that most significantly impact Shoreditch’s economic performance. GEUK accounts for the difference between the purchase price of Shoreditch’s equity and its share of the underlying equity in the net assets of Shoreditch as if Shoreditch were a consolidated subsidiary. The difference of $0.5 million was allocated to goodwill. The goodwill relates to EGC’s contribution to Shoreditch of their knowledge, experience and detailed business plan for operating a REP in the United Kingdom. In December 2017, Shoreditch commenced initial customer acquisition in the United Kingdom under the mandated three-month Controlled Market Entry framework in which new entrants can acquire a limited number of customers in a test environment. The following table summarizes the change in the balance of GEUK’s investment in Shoreditch in the year ended December 31, 2017 (in thousands): Balance, beginning of period $ — Capital contributions 3,970 Cumulative foreign currency translation adjustment 45 Equity in the net loss of joint venture (565 ) Balance, end of period $ 3,450 At December 31, 2017, the Company’s maximum exposure to loss as a result of its involvement with Shoreditch was its $3.5 million investment, since there were no other arrangements, events or circumstances that could expose the Company to additional loss. Summarized statement of operations of Shoreditch from July 17, 2017 through December 31, 2017 (in thousands) is as follows: REVENUES $ — OPERATING EXPENSES: Cost of revenues 8 Selling, general and administrative 779 TOTAL OPERATING EXPENSES 787 Loss from operations (787 ) Other — NET LOSS $ (787 ) Summarized balance sheet of Shoreditch at December 31, 2017 (in thousands) is as follows: Assets Cash and cash equivalents $ 2,787 Other current assets 79 Other assets 189 Total assets $ 3,055 Liabilities and member’s interest Current liabilities $ 18 Member’s interest 3,037 Total liabilities and member’s interest $ 3,055

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2017
Property and Equipment [Abstract]
Property and Equipment	Note 7 — Property and Equipment December 31 (in thousands) 2017 2016 Computer software and development $ 1,912 $ 1,836 Computers and computer hardware 246 231 Laboratory and drilling equipment 3,833 543 Office equipment and other 443 424 6,434 3,034 Less: accumulated depreciation (2,414 ) (1,417 ) Property and equipment, net $ 4,020 $ 1,617 Depreciation expense of property and equipment was $0.8 million, $0.4 million and $0.4 million in the years ended December 31, 2017, 2016 and 2015, respectively.

Goodwill and Other Intangibles

Goodwill and Other Intangibles	12 Months Ended
	Dec. 31, 2017
Goodwill and Other Intangibles [Abstract]
Goodwill and Other Intangibles	Note 8 — Goodwill and Other Intangibles All of the Company’s goodwill at December 31, 2017 and 2016 was attributable to the GRE segment. The table below reconciles the change in the carrying amount of goodwill for the period from December 31, 2014 to December 31, 2017: (in thousands) Balance at December 31, 2014 $ 3,663 Change in carrying amount — Balance at December 31, 2015 3,663 Acquisition of Retail Energy Holdings, LLC (see Note 2) 5,065 Balance at December 31, 2016 8,728 Acquisition of Mirabito Natural Gas (see Note 2) 1,270 Balance at December 31, 2017 $ 9,998 The table below presents information on the Company’s other intangible assets: (in thousands) Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net December 31, 2017 Patents and trademarks 20 years $ 2,860 $ (135 ) $ 2,725 Non-compete agreement 2 years 115 (65 ) 50 Customer relationships 4.4 years 3,200 (1,266 ) 1,934 Licenses — 150 — 150 TOTAL 11.3 years $ 6,325 $ (1,466 ) $ 4,859 December 31, 2016 Trademark 20 years $ 2,100 $ (13 ) $ 2,087 Non-compete agreement 2 years 110 (11 ) 99 Customer relationships 2 years 2,100 (159 ) 1,941 Licenses — 150 — 150 TOTAL 10.4 years $ 4,460 $ (183 ) $ 4,277 Amortization expense of intangible assets was $1.3 million, $0.2 million and nil in in the years ended December 31, 2017, 2016 and 2015, respectively. The Company estimates that amortization expense of intangible assets with finite lives will be $1.2 million, $0.3 million, $0.3 million, $0.3 million and $0.3 million in the years ending December 31, 2018, 2019, 2020, 2021 and 2022, respectively.

Revolving Lines of Credit

Revolving Lines of Credit	12 Months Ended
	Dec. 31, 2017
Revolving Lines of Credit [Abstract]
Revolving Lines of Credit	Note 9 — Revolving Lines of Credit On April 4, 2017, GRE, IDT Energy, and other GRE subsidiaries entered into a Credit Agreement with Vantage Commodities Financial Services II, LLC (“Vantage”) for a $20 million revolving line of credit. The borrowers consist of the Company’s subsidiaries that operate REP businesses, and those subsidiaries’ obligations are guaranteed by GRE. On April 4, 2017, the borrowers borrowed $4.3 million under this facility, which included $1.7 million that was previously outstanding under a credit facility between REH and Vantage. The REH Credit Agreement with Vantage was terminated in connection with the entry into this credit agreement, which was treated as a modification. The borrowers have provided as collateral a security interest in their receivables, bank accounts, customer agreements, certain other material agreements and related commercial and intangible rights. The outstanding principal amount incurs interest at LIBOR plus 4.5% per annum. Interest is payable monthly and all outstanding principal and any accrued and unpaid interest is due on the maturity date of April 3, 2020. At December 31, 2017, $2.5 million was outstanding under the revolving line of credit and the effective interest rate was 5.99% per annum. The borrowers are required to comply with various affirmative and negative covenants, including maintaining a target tangible net worth during the term of the credit agreement. To date, the Company is in compliance with such covenants. REH had a Credit Agreement with Vantage for a revolving line of credit for up to a maximum principal amount of $7.5 million (see above). The principal outstanding incurred interest at one-month LIBOR plus 5.25% per annum, payable monthly. The outstanding principal and any accrued and unpaid interest was due on the maturity date of October 31, 2017. At December 31, 2016, $0.7 million was outstanding under the line of credit. The Company and IDT Energy had a Loan Agreement with JPMorgan Chase Bank for a revolving line of credit for up to a maximum principal amount of $25.0 million. The principal outstanding incurred interest at the lesser of (a) the LIBOR rate multiplied by the statutory reserve rate established by the Board of Governors of the Federal Reserve System plus 1.0% per annum, or (b) the maximum rate per annum permitted by whichever of applicable federal or Texas laws permit the higher interest rate. Interest was payable at least every three months and any outstanding principal and accrued and unpaid interest was due on the maturity date of May 31, 2017. The Company agreed to deposit cash in a money market account at JPMorgan Chase Bank as collateral for the line of credit equal to the greater of (a) $10.0 million or (b) the sum of the amount of letters of credit outstanding plus the outstanding principal under the revolving note. At December 31, 2016, there were no amounts borrowed under the line of credit, and cash collateral of $10.0 million was included in “Restricted cash—short-term” in the consolidated balance sheet. In addition, at December 31, 2016, letters of credit of $8.1 million were outstanding. On May 31, 2017, the $10.0 million cash collateral was released upon expiration of the Loan Agreement. On December 17, 2015, GRE, IDT Energy and certain affiliates entered into a Credit Agreement with Maple Bank GmbH for a revolving loan facility. On December 17, 2015, GRE borrowed $2.0 million under the facility. In February 2016, the German banking regulator, Bafin, closed Maple Bank GmbH due to impending financial over-indebtedness related to tax-evasion investigations. In September 2016, GRE, and its affiliates entered into a settlement agreement with the court appointed liquidator of Maple Bank. Under this agreement, GRE paid $1.8 million as a full settlement of all of its obligations, and the revolving loan facility was terminated. Accordingly, in 2016, GRE recorded a gain from this settlement of $0.2 million, which was included in “Other (expense) income, net” in the consolidated statements of operations.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Taxes	Note 10 — Income Taxes On December 22, 2017, the U.S. government enacted “An Act to Provide for Reconciliation Pursuant to Titles II and V of the Concurrent Resolution on the Budget for Fiscal Year 2018”, which is commonly referred to as “The Tax Cuts and Jobs Act” (the “Tax Act”). The Tax Act provides for comprehensive tax legislation that reduces the U.S. federal statutory corporate tax rate from 35.0% to 21.0% effective January 1, 2018, broadens the U.S. federal income tax base, requires companies to pay a one-time repatriation tax on earnings of certain foreign subsidiaries that were previously tax deferred (“transition tax”), and creates new taxes on certain foreign sourced earnings. On December 22, 2017, the SEC issued Staff Accounting Bulletin No. 118 (“SAB 118”), expressing its views regarding the FASB’s Accounting Standards Codification 740, Income Taxes, in the reporting period that includes the enactment date of the Tax Act. SAB 118 recognizes that a registrant’s review of certain income tax effects of the Tax Act may be incomplete at the time financial statements are issued for the reporting period that includes the enactment date, including interim periods therein. Specifically, SAB 118 allows a company to report provisional estimates in the reporting period that includes the enactment date if the company does not have the necessary information available, prepared, or fully analyzed for certain income tax effects of the Tax Act. The provisional estimates would be adjusted during a measurement period not to exceed 12 months from the enactment date of the Tax Act, at which time the accounting for the income tax effects of the Tax Act is required to be completed. The Company has not completed its accounting for the income tax effects of the enactment of the Tax Act; however, the Company has made a reasonable estimate of the effect on its existing deferred tax assets and corresponding valuation allowance. The table below in this footnote reflects the new income tax rate. The transition tax is based on total post-1986 earnings and profits which were previously deferred from U.S. income taxes. At December 31, 2017, the Company did not have any undistributed earnings of our foreign subsidiaries. As a result, no additional income or withholding taxes have been provided for, for the undistributed earnings or any additional outside basis differences inherent in the foreign entities. The Company continues to review the anticipated impacts of the global intangible low taxed income (“GILTI”) and base erosion anti-abuse tax (“BEAT). The Company has not recorded any impact associated with either GILTI or BEAT. The Company anticipates that its assumptions and estimates may change as a result of future guidance and interpretation from the Internal Revenue Service, the SEC, the FASB, and various other taxing jurisdictions. In particular, the Company anticipates that the U.S. state jurisdictions will continue to determine and announce their conformity with or decoupling from the Tax Act, either in its entirety or with respect to specific provisions. Legislative and interpretive actions could result in adjustments to the Company’s provisional estimates when the accounting for the income tax effects of the Tax Act is completed. The Company will continue to evaluate the impact of the Tax Act on its financial statements, and will record the effect of any reasonable changes in its estimates and adjustments. The components of income (loss) before income taxes are as follows: Year ended December 31, (in thousands) 2017 2016 2015 Domestic $ 7,122 $ 18,629 $ 1,517 Foreign (14,044 ) (48,603 ) (9,628 ) LOSS BEFORE INCOME TAXES $ (6,922 ) $ (29,974 ) $ (8,111 ) Significant components of the Company’s deferred income tax assets consist of the following: December 31 (in thousands) 2017 2016 Deferred income tax assets: Bad debt reserve $ 302 $ 70 Accrued expenses 4,425 3,821 State taxes 117 221 Charitable contributions 265 470 Net operating loss 37,435 37,568 Stock options and restricted stock 908 1,456 Depreciation 7,026 11,153 Total deferred income tax assets 50,478 54,759 Valuation allowance (48,337 ) (52,978 ) DEFERRED INCOME TAX ASSETS, NET $ 2,141 $ 1,781 The Company recognizes deferred tax assets to the extent that it believes that these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, the Company would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The (provision for) benefit from income taxes consists of the following: Year ended December 31, (in thousands) 2017 2016 2015 Current: Federal $ — $ — $ — State and local (1,366 ) (2,349 ) (704 ) Foreign — (8 ) — (1,366 ) (2,357 ) (704 ) Deferred: Federal — (6 ) (19 ) State and local (360 ) 145 198 Foreign — — — (360 ) 139 179 PROVISION FOR INCOME TAXES $ (1,726 ) $ (2,218 ) $ (525 ) The differences between income taxes expected at the U.S. federal statutory income tax rate and income taxes provided are as follows: Year ended December 31, (in thousands) 2017 2016 2015 U.S. federal income tax benefit at statutory rate $ 2,423 $ 10,491 $ 2,840 Valuation allowance 11,694 (21,209 ) (10,687 ) Foreign tax rate differential (2,610 ) 9,901 7,674 Tax law change (11,070 ) — — Deferred income tax adjustment (1,250 ) — — Other 66 95 (20 ) State and local income tax, net of federal benefit (979 ) (1,496 ) (332 ) PROVISION FOR INCOME TAXES $ (1,726 ) $ (2,218 ) $ (525 ) At December 31, 2017, the Company had U.S. federal and state net operating loss carry-forwards of approximately $30.5 million and $113.4 million, respectively. These carry-forward losses are available to offset future U.S. federal and state taxable income. The federal net operating loss carry-forwards will start to expire in 2033, with the year ended December 31, 2017’s loss expiring in 2037. The state net operating loss carry-forwards will start to expire in 2029, with the year ended December 31, 2017’s loss expiring in 2038. At December 31, 2017, the Company had foreign net operating loss carry-forwards of approximately $98.4 million, of which $89.8 million will not expire. The Company includes certain entities that are not included in the Company’s consolidated tax return. The entities have separate U.S. federal and state net operating loss carry-forwards of $1.0 million that begin to expire in 2036. The change in the valuation allowance for deferred income taxes was as follows: (in thousands) Balance at beginning of period Additions charged to costs and expenses Deductions Balance at end of period Year ended December 31, 2017 Reserves for valuation allowances deducted from deferred income taxes, net $ 52,978 $ 7,053 $ (11,694 ) $ 48,337 Year ended December 31, 2016 Reserves for valuation allowances deducted from deferred income taxes, net $ 31,769 $ 21,209 $ — $ 52,978 Year ended December 31, 2015 Reserves for valuation allowances deducted from deferred income taxes, net $ 21,082 $ 10,687 $ — $ 31,769 The table below summarizes the change in the balance of unrecognized income tax benefits: Year ended December 31, (in thousands) 2017 2016 2015 Balance at beginning of period $ 632 $ 636 $ 543 Additions based on tax positions related to the 100 81 97 Additions for tax positions of prior periods 1 4 10 Lapses of statutes of limitations (175 ) (89 ) (14 ) Balance at end of period $ 558 $ 632 $ 636 All of the unrecognized income tax benefits at December 31, 2017 and 2016 would have affected the Company’s effective income tax rate if recognized. The Company does not expect the total amount of unrecognized income tax benefits to significantly increase or decrease within the next twelve months. In the years ended December 31, 2017, 2016 and 2015, the Company recorded interest on income taxes of $1,000, $4,000 and $4,000, respectively. At December 31, 2017 and 2016, there was accrued interest of $35,000 and $34,000 included in current income taxes payable. The Company currently remains subject to examinations of its tax returns as follows: U.S. federal tax returns for 2014 to 2017, state and local tax returns generally for 2013 to 2017 and foreign tax returns generally for 2013 to 2017.

Equity

Equity	12 Months Ended
	Dec. 31, 2017
Equity & Accumulated Other Comprehensive Income [Abstract]
Equity	Note 11 — Equity Class A Common Stock and Class B Common Stock The rights of holders of Class A common stock and Class B common stock are identical except for certain voting and conversion rights and restrictions on transferability. The holders of Class A common stock and Class B common stock receive identical dividends per share when and if declared by the Company’s Board of Directors. In addition, the holders of Class A common stock and Class B common stock have identical and equal priority rights per share in liquidation. The Class A common stock and Class B common stock do not have any other contractual participation rights. The holders of Class A common stock are entitled to three votes per share and the holders of Class B common stock are entitled to one-tenth of a vote per share. Except as required by law or under the terms of the Series 2012-A Preferred Stock (the “Preferred Stock”), the holders of Class A and Class B common stock and the Preferred Stock vote together as a single class on all matters submitted to a vote of the Company’s stockholders. Each share of Class A common stock may be converted into one share of Class B common stock, at any time, at the option of the holder. Shares of Class A common stock are subject to certain limitations on transferability that do not apply to shares of Class B common stock. Series 2012-A Preferred Stock Each share of Preferred Stock has a liquidation preference of $8.50 (the “Liquidation Preference”), and is entitled to receive an annual dividend per share equal to the sum of (i) $0.6375 (the “Base Dividend”) plus (ii) seven and one-half percent (7.5%) of the quotient obtained by dividing (A) the amount by which the EBITDA for a fiscal year of the Company’s retail energy provider business exceeds $32 million by (B) 8,750,000 (the “Additional Dividend”), payable in cash. EBITDA consists of income (loss) from operations exclusive of depreciation and amortization and other operating gains (losses). During any period when the Company has failed to pay a dividend on the Preferred Stock and until all unpaid dividends have been paid in full, the Company is prohibited from paying dividends or distributions on the Company’s Class B or Class A common stock. The Preferred Stock is redeemable, in whole or in part, at the option of the Company following October 11, 2017 at 101% of the Liquidation Preference plus accrued and unpaid dividends, and 100% of the Liquidation Preference plus accrued and unpaid dividends following October 11, 2018. The Base Dividend is payable (if declared by the Company’s Board of Directors, and accrued, if not declared) quarterly on each February 15, May 15, August 15 and November 15, and to the extent that there is any Additional Dividend payable with respect to a fiscal year, it will be paid to holders of Preferred Stock with the May dividend. With respect to the payment of dividends and amounts upon liquidation, dissolution or winding up, the Preferred Stock is equal in rank to all other equity securities the Company issues, the terms of which specifically provide that such equity securities rank on a parity with the Preferred Stock with respect to dividend rights or rights upon the Company’s liquidation, dissolution or winding up; senior to the Company’s common stock; and junior to all of the Company’s existing and future indebtedness. Each share of Preferred Stock has the same voting rights as a share of Class B common stock, except on certain matters that only impact the Company’s common stock, as well as additional voting rights on specific matters or upon the occurrence of certain events. Dividend Payments In the year ended December 31, 2017, the Company paid aggregate cash dividends of $0.30 per share on its Class A common stock and Class B common stock, equal to $7.4 million in total dividends paid. In the year ended December 31, 2016, the Company paid aggregate cash dividends of $0.24 per share on its Class A common stock and Class B common stock, equal to $5.9 million in total dividends paid. In the year ended December 31, 2015, the Company paid aggregate cash dividends of $0.12 per share on its Class A common stock and Class B common stock, equal to $3.0 million in total dividends paid. In March 2018, the Company’s Board of Directors declared a quarterly dividend of $0.075 per share on the Company’s Class A common stock and Class B common stock for the fourth quarter of 2017 to stockholders of record as of the close of business on March 19, 2018. The dividend will be paid on or about March 23, 2018. In each of the years ended December 31, 2017, 2016 and 2015, the Company paid aggregate cash dividends of $0.6376 per share on its Preferred Stock, equal to $1.5 million in dividends paid. On February 15, 2018, the Company paid a quarterly Base Dividend of $0.1594 per share on its Preferred Stock for the fourth quarter of 2017 to stockholders of record as of the close of business on February 6, 2018. Stock Repurchases On March 11, 2013, the Board of Directors of the Company approved a stock repurchase program for the repurchase of up to an aggregate of 7.0 million shares of the Company’s Class B common stock. There were no repurchases under the program in the years ended December 31, 2017, 2016 and 2015. At December 31, 2017, 6.9 million shares remained available for repurchase under the stock repurchase program. In the year ended December 31, 2017, the Company paid $0.8 million to repurchase 129,898 shares of its Class B common stock. In the year ended December 31, 2016, the Company paid $29,000 to repurchase 3,096 shares of its Class B common stock. In the year ended December 31, 2015, the Company paid $27,000 to repurchase 4,220 shares of its Class B common stock. These shares were tendered by the Company’s employees to satisfy tax withholding obligations in connection with the lapsing of restrictions on awards of restricted stock. Such shares were repurchased by the Company based on their fair market value on the trading day immediately prior to the vesting date. Repurchase Right on Sale of Shares to Howard S. Jonas On July 30, 2014, the Company entered into a Second Amended and Restated Employment Agreement and a Restricted Stock Sale Agreement with Howard S. Jonas, the Company’s Chairman of the Board and former Chief Executive Officer. Pursuant to these agreements, among other things, in 2014, the Company sold an aggregate of 3.6 million shares of the Company’s Class B common stock to Mr. Jonas at a price of $6.82 per share (the closing price per share of the Class B common stock on the day that the arrangement was approved by the Company’s Board of Directors and Compensation Committee). Upon certain terminations of Mr. Jonas’ employment by the Company, 0.6 million of the Class B shares are subject to repurchase by the Company at $6.82 per share, which repurchase right lapses on December 31, 2018. Sales of Equity of Subsidiaries In December 2016, Afek sold a 1% equity interest to Dr. Harold Vinegar, former Chief Scientist of the Company, for $1.0 million in cash. In November 2010, GOGAS sold a 0.5% equity interest to Rupert Murdoch for $1.0 million paid with a promissory note. The note was secured by a pledge of the shares issued in exchange for the note. The note accrued interest at 1.58% per annum. The Company received an aggregate of $1.1 million for the payment of the principal and accrued interest on the maturity date of November 15, 2015. Purchases of Equity of Subsidiary In the year ended December 31, 2017, GOGAS purchased from employees of Afek a 1.15% fully vested interest in Afek for $0.3 million in cash. Exercise of GOGAS Stock Option GOGAS issued a stock option in June 2011 to Michael Steinhardt, the Chairman of the Board of Israel Energy Initiatives, Ltd. (“IEI”), at an exercise price of $5.0 million. The expiration date was April 9, 2015. The expiration date was extended for one month, and on May 9, 2015, the option was exercised. Mr. Steinhardt and an affiliate received interests of approximately 1.5% in each of Afek, Genie Mongolia and IEI. In addition, Mr. Steinhardt and the affiliate received an approximately 1.7% interest in AMSO. The exercise price of $5.0 million was paid $2.5 million in cash and $2.5 million in promissory notes that were due in November 2015. The notes incurred interest at 0.43% per annum, and were secured by 50% of the shares received in the exercise. In November 2015, the Company received cash of $0.8 million to repay one-third of the principal amount of the promissory notes, and released one-third of the shares securing the remaining notes. Effective December 31, 2017, the remaining notes, an aggregate of $1.7 million, were cancelled and the pledged shares were transferred to GOGAS. At December 31, 2016, the notes receivable were included in “Receivables for issuance of equity” in the consolidated balance sheet. Subsequent Event — Proposed Sales of Shares and Warrants On February 15, 2018, the Board of Directors of the Company approved, subject to stockholder approval at the Company’s annual meeting to be held on May 7, 2018, the sale of (1) 1,152,074 shares of the Company’s Class B common stock, at a price of $4.34 per share for an aggregate sales price of $5.0 million, and (2) warrants to purchase an additional 1,048,218 shares of the Company’s Class B common stock at an exercise price of $4.77 per share for an aggregate exercise price of $5.0 million, to Howard S. Jonas or his affiliates. The warrants will expire two years from the closing of the sale, which will take place as soon as practicable following stockholder approval, if obtained. In addition, the Board of Directors approved, upon the same terms, the sale of up to 230,415 shares of the Company’s Class B common stock and warrants to purchase an additional 209,644 shares of the Company’s Class B common stock to a third-party investor, subject to agreement of that investor. The price for the sale of the shares is equal to the closing price of the Class B common stock on the day before the transaction was first considered by the Board of Directors. The exercise price of the warrants represents a 10% premium on the sale price.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Stock-Based Compensation [Abstract]
Stock-Based Compensation	Note 12 — Stock-Based Compensation Stock-Based Compensation Plan The Company’s 2011 Stock Option and Incentive Plan is intended to provide incentives to executives, employees, directors and consultants of the Company. Incentives available under the 2011 Stock Option and Incentive Plan may include stock options, stock appreciation rights, limited rights, deferred stock units, and restricted stock. The plan is administered by the Compensation Committee of the Company’s Board of Directors. At December 31, 2017, the Company had 1.3 million shares of Class B common stock reserved for award under its 2011 Stock Option and Incentive Plan and 51,000 shares were available for future grants. Restricted Stock The fair value of restricted shares of the Company’s Class B common stock is determined based on the closing price of the Company’s Class B common stock on the grant date. Share awards generally vest on a graded basis over three years of service following the grant. A summary of the status of the Company’s grants of restricted shares of Class B common stock is presented below: Number of Non-vested Shares (in thousands) Weighted- Average Grant Date Fair Value Non-vested shares at December 31, 2016 26 $ 10.08 Granted 182 5.77 Vested (45 ) 8.36 Forfeited — — NON-VESTED SHARES AT DECEMBER 31, 2017 163 $ 6.19 At December 31, 2017, there was $3.7 million of total unrecognized compensation cost related to non-vested stock-based compensation arrangements, mostly related to the shares purchased by Howard S. Jonas in 2014. The total unrecognized compensation cost is expected to be recognized over a weighted-average period of 0.8 years. The total grant date fair value of shares vested in the years ended December 31, 2017, 2016 and 2015 was $0.4 million, $0.5 million and $0.5 million, respectively. The Company recognized compensation cost related to the vesting of the restricted stock of $3.1 million, $3.5 million, and $3.6 million in the years ended December 31, 2017, 2016, and 2015, respectively. Stock Options Option awards are generally granted with an exercise price equal to the market price of the Company’s stock on the date of grant. Option awards generally vest on a graded basis over three years of service and have ten-year contractual terms. Expected volatility is based on historical volatility of the Company’s Class B common stock and other factors. The Company uses historical data on exercise of stock options, post vesting forfeitures and other factors to estimate the expected term of the stock-based payments granted. The risk free rate is based on the U.S. Treasury yield curve in effect at the time of grant. The fair value of stock options granted in the years ended December 31, 2016 and 2015 was estimated on the date of the grant using a Black-Scholes valuation model and the assumptions in the following table. No option awards were granted in the year ended December 31, 2017. Year ended December 31, 2016 2015 ASSUMPTIONS Average risk-free interest rate 0.4 % 0.93 % Expected dividend yield 5.01 % — Expected volatility 55.5 % 61.0 % Expected term 1 year 5.5 years Weighted-average grant date fair value of options granted $ 1.05 $ 9.67 A summary of stock option activity for the Company is as follows: Number of Options Weighted- Average Exercise Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at December 31, 2016 414 $ 6.75 4.6 $ 37 Granted — — Exercised (16 ) 6.85 Cancelled/Forfeited (15 ) 4.05 OUTSTANDING AT DECEMBER 31, 2017 383 $ 6.85 3.8 $ — EXERCISABLE AT DECEMBER 31, 2017 327 $ 6.85 3.8 $ — The total intrinsic value of options exercised during the years ended December 31, 2017, 2016 and 2015 was $13,000, nil and $12,000, respectively. At December 31, 2017, there was $0.1 million of total unrecognized compensation cost related to non-vested stock options, which is expected to be recognized over a weighted-average period of 1.1 years. The Company recognized compensation cost related to the vesting of the options of $35,000, $23,000 and $0.3 million in the years ended December 31, 2017, 2016 and 2015, respectively. Subsidiary Equity Grants Reclassified to Liability On May 5, 2015, the Compensation Committee of the Company’s Board of Directors approved the grant of deferred stock units in GRE representing an aggregate of 3.9% of the outstanding equity in GRE to certain of the Company’s officers and employees. The deferred stock units vest in equal amounts on the first, second and third anniversaries of the date of grant. The fair value of the GRE deferred stock units on the date of grant was $3.3 million, which is being recognized on a straight-line basis over the requisite service period, which approximates the vesting period. GRE has the right to issue shares of the Company’s Class B common stock or pay cash to satisfy its obligations to issue common stock of GRE upon the vesting of the deferred stock units. GRE elected to pay cash for the deferred stock units that vested in June and July 2016. The Company paid cash in the amount of $1.7 million in August 2016 to satisfy its obligation to issue common stock of GRE. Because of the cash settlement, the Company determined that the remaining GRE deferred stock units should be classified as a liability. In August 2017, GRE elected to exchange shares of the Company’s Class B common stock for the vested deferred stock units based on the relative fair value of the shares exchanged. The Company issued 287,233 shares of its Class B common stock in exchange for 26.1 vested deferred stock units of GRE. The aggregate fair value of the shares of the Company’s Class B common stock issued was $1.8 million. At December 31, 2017 and 2016, $0.8 million and $0.7 million, respectively, related to the GRE deferred stock units was included in “Other current liabilities” in the consolidated balance sheet. In August 2015, the Company elected to pay cash of $1.2 million for the deferred stock units of IDT Energy previously granted to employees and directors of the Company that vested in June and July 2015 based on the estimated fair value of the deferred stock units of IDT Energy. The Company recognized aggregate compensation cost related to the vesting of the deferred stock units and other subsidiary equity interests that were granted in prior years of $2.1 million, $0.6 million and $1.4 million in the years ended December 31, 2017, 2016 and 2015, respectively. At December 31, 2017, there was $1.0 million of total unrecognized compensation cost related to non-vested subsidiary equity interests, which is expected to be recognized over a weighted-average period of 0.4 years.

Variable Interest Entity

Variable Interest Entity	12 Months Ended
	Dec. 31, 2017
Variable Interest Entity [Abstract]
Variable Interest Entity	Note 13 — Variable Interest Entity Citizens Choice Energy, LLC (“CCE”) is a REP that resells electricity and natural gas to residential and small business customers in the State of New York. The Company does not own any interest in CCE. Since 2011, the Company provided CCE with substantially all of the cash required to fund its operations. The Company determined that it has the power to direct the activities of CCE that most significantly impact its economic performance and it has the obligation to absorb losses of CCE that could potentially be significant to CCE on a stand-alone basis. The Company therefore determined that it is the primary beneficiary of CCE, and as a result, the Company consolidates CCE within its GRE segment. The net income or loss incurred by CCE was attributed to noncontrolling interests in the accompanying consolidated statements of operations. In October 2015, GRE paid $0.2 million to the owner of the limited liability company interests in CCE, and loaned CCE $0.5 million in exchange for an option to purchase 100% of the issued and outstanding limited liability company interests of CCE for one dollar plus the forgiveness of the $0.5 million loan. The option expires on October 22, 2023. Net income (loss) related to CCE and aggregate net funding repaid to (provided by) the Company were as follows: Year ended December 31, (in thousands) 2017 2016 2015 Net income (loss) $ 112 $ (1,136 ) $ 34 Aggregate funding repaid to (provided by) the Company, net 158 (871 ) 950 Summarized consolidated balance sheet amounts related to CCE are as follows: December 31 (in thousands) 2017 2016 ASSETS Cash and cash equivalents $ 52 $ 150 Restricted cash 31 17 Trade accounts receivable 1,031 1,008 Prepaid expenses 451 450 Other current assets 31 26 Other assets 439 439 TOTAL ASSETS $ 2,035 $ 2,090 LIABILITIES AND NONCONTROLLING INTERESTS Current liabilities $ 698 $ 707 Due to IDT Energy 1,140 1,298 Noncontrolling interests 197 85 TOTAL LIABILITIES AND NONCONTROLLING INTERESTS $ 2,035 $ 2,090 The assets of CCE may only be used to settle obligations of CCE, and may not be used for other consolidated entities. The liabilities of CCE are non-recourse to the general credit of the Company’s other consolidated entities.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2017
Equity & Accumulated Other Comprehensive Income [Abstract]
Accumulated Other Comprehensive Income	Note 14 — Accumulated Other Comprehensive Income The accumulated balances for other comprehensive income were as follows: (in thousands) Foreign currency translation Balance at December 31, 2014 $ 10 Other comprehensive income attributable to Genie 144 Balance at December 31, 2015 154 Other comprehensive income attributable to Genie 1,311 Balance at December 31, 2016 1,465 Other comprehensive income attributable to Genie 1,580 BALANCE AT DECEMBER 31, 2017 $ 3,045

Legal and Regulatory Proceeding

Legal and Regulatory Proceedings	12 Months Ended
	Dec. 31, 2017
Legal and Regulatory Proceedings [Abstract]
Legal and Regulatory Proceedings	Note 15 — Legal and Regulatory Proceedings Legal Proceedings On March 13, 2014, named plaintiff, Anthony Ferrare, commenced a putative class-action lawsuit against IDT Energy, Inc. in the Court of Common Pleas of Philadelphia County, Pennsylvania. The complaint was served on IDT Energy on July 16, 2014. The named plaintiff filed the suit on behalf of himself and other former and current electric customers of IDT Energy in Pennsylvania with variable rate plans, whom he contends were injured as a result of IDT Energy’s allegedly unlawful sales and marketing practices. On August 7, 2014, IDT Energy removed the case to the United States District Court for the Eastern District of Pennsylvania. On October 20, 2014, IDT Energy moved to stay or, alternatively, dismiss the complaint, as amended, by the named plaintiff. On November 10, 2014, the named plaintiff opposed IDT Energy’s motion to dismiss and IDT Energy filed a reply memorandum of law in further support of its motion to dismiss. On June 10, 2015, the Court granted IDT Energy’s motion to stay and denied its motion to dismiss without prejudice. The parties participated in mediation, and subsequently entered into a Settlement Agreement (see below), which received preliminary approval from the Court on October 16, 2017. The Settlement Agreement is subject to entry of a final order by the Court approving the Settlement Agreement. The Court has scheduled a hearing concerning final approval for April 9, 2018. On July 2, 2014, named plaintiff, Louis McLaughlin, filed a putative class-action lawsuit against IDT Energy, Inc. in the United States District Court for the Eastern District of New York, contending that he and other class members were injured as a result of IDT Energy’s allegedly unlawful sales and marketing practices. The named plaintiff filed the suit on behalf of himself and two subclasses: all IDT Energy customers who were charged a variable rate for their energy from July 2, 2008, and all IDT Energy customers who participated in IDT Energy’s rebate program from July 2, 2008. On January 22, 2016, the named plaintiff filed an amended complaint on behalf of himself and all IDT Energy customers in New York State against IDT Energy, Inc., Genie Retail Energy, Genie Energy International Corporation, and Genie Energy Ltd. (collectively, “IDT Energy”). On February 22, 2016, IDT Energy moved to dismiss the amended complaint, and the named plaintiff opposed that motion. The parties participated in mediation, and subsequently entered into a Settlement Agreement (see below), which received preliminary approval from the Court on October 16, 2017. The Settlement Agreement is subject to entry of a final order by the Court approving the Settlement Agreement. The Court has scheduled a hearing concerning final approval for April 9, 2018. On July 15, 2014, named plaintiff, Kimberly Aks, commenced a putative class-action lawsuit against IDT Energy, Inc. in New Jersey Superior Court, Essex County, contending that she and other class members were injured as a result of IDT Energy’s alleged unlawful sales and marketing practices. The named plaintiff filed the suit on behalf of herself and all other New Jersey residents who were IDT Energy customers at any time between July 11, 2008 and the present. The parties were engaged in discovery prior to the mediation described below. On April 20, 2016, the named plaintiff filed an amended complaint on behalf of herself and all IDT Energy customers in New Jersey against IDT Energy, Inc., Genie Retail Energy, Genie Energy International Corporation and Genie Energy Ltd. On June 27, 2016, defendants Genie Retail Energy, Genie Energy International Corporation and Genie Energy Ltd. filed a motion to dismiss the amended complaint. On August 26, 2016, the named plaintiff opposed that motion and IDT Energy filed a reply memorandum of law in further support of its motion to dismiss. The Court granted the motion to dismiss, but the parties agreed to set aside that decision to give the plaintiff an opportunity to submit opposition papers that had not been considered by the Court in rendering its decision. The parties participated in mediation, and subsequently entered into a Settlement Agreement (see below), which received preliminary approval from the Court on October 16, 2017. The Settlement Agreement is subject to entry of a final order by the Court approving the Settlement Agreement. The Court has scheduled a hearing concerning final approval for April 9, 2018. On July 5, 2017, the Company entered into a class action Settlement Agreement with the class action plaintiffs acting individually and on behalf of the entire class, in the lawsuits currently pending in Pennsylvania, New York, and New Jersey described above. The Company does not believe that there was any wrongdoing on its part, and is entering into this settlement to further its efforts to address its customers’ concerns. Under the Settlement Agreement, the Company has agreed to pay certain amounts to resolve the lawsuits and obtain a release of claims that were asserted or could be asserted in the lawsuits or that are related to or arise out of the conduct alleged in the lawsuits or similar conduct, wherever it may have occurred. The settlement payment includes payments to customers who timely make a claim, class counsel, and the named plaintiffs as well as the cost of a claims administrator for administrating the claims process. The Company estimated, based in part on historical participation rates that its total settlement payment will be approximately $9 million, although it is reasonably possible that the total payments could reach $10.1 million. In the year ended December 31, 2017, the Company recorded a revenue reduction of $3.6 million and an expense of $5.4 million that is included in “Selling, general and administrative expense”, and a liability of $9.0 million. The actual amount to be paid out will depend on several factors, including the number of customers who claim settlement payments to which they are entitled. The Settlement Agreement was preliminarily approved by the Court on October 16, 2017. The Settlement Agreement is subject to entry of a final order by the Court approving the Settlement Agreement. The Court has scheduled a hearing concerning final approval for April 9, 2018. On June 20, 2014, the Pennsylvania Attorney General’s Office (“AG”) and the Acting Consumer Advocate (“OCA”) filed a Joint Complaint against IDT Energy, Inc. with the Pennsylvania Public Utility Commission (“PUC”). In the Joint Complaint, the AG and the OCA alleged, among other things, various violations of Pennsylvania’s Unfair Trade Practices and Consumer Protection Law, the Telemarketing Registration Act and the PUC’s regulations. IDT Energy reached an agreement in principle on a settlement with the AG and the OCA to terminate the litigation with no admission of liability or finding of wrongdoing by IDT Energy. On August 4, 2015, IDT Energy, the AG, and the OCA filed a Joint Petition to the Pennsylvania PUC seeking approval of the settlement terms. Under the settlement, IDT Energy will issue additional refunds to its Pennsylvania customers who had variable rates for electricity supply in January, February and March of 2014. IDT Energy will also implement certain modifications to its sales, marketing and customer service processes, along with additional compliance and reporting requirements. The settlement was approved by the Pennsylvania PUC on July 8, 2016. In July 2016, IDT Energy paid the agreed-upon $2.4 million for additional customer refunds to a refund administrator. In the fourth quarter of 2015, the Company received a request for information from the New Jersey Office of the Attorney General. The Company responded to the inquiry. The Company has recently been engaged in discussions with the New Jersey Office of the Attorney General regarding concerns raised by the New Jersey Board of Public Utilities and Division of Consumer Affairs related to energy supply charges issued to the Company’s retail customers during the first quarter of 2014 and have reached a tentative agreement in principle. In the year ended December 31, 2017, the Company accrued $1.5 million of estimated loss related to this matter. The Company recorded a revenue reduction in the consolidated statement of operations of $1.3 million relating to refunds to customers and an expense of $0.2 million for related fees that is included in “Selling, general and administrative expense,” and a liability of $1.5 million that is included in “Accrued expenses” in the consolidated balance sheet. From time to time, the Company receives inquiries or requests for information or materials from public utility commissions or other governmental regulatory or law enforcement agencies related to investigations under statutory or regulatory schemes, and the Company responds to those inquiries or requests. The Company cannot predict whether any of those matters will lead to claims or enforcement actions. In addition to the above, the Company may from time to time be subject to legal proceedings that arise in the ordinary course of business. Although there can be no assurance in this regard, the Company does not expect any of those legal proceedings to have a material adverse effect on the Company’s results of operations, cash flows or financial condition. New York Public Service Commission Orders On February 23, 2016, the New York Public Service Commission (“PSC”) issued an order that sought to impose significant new restrictions on REPs operating in New York, including those owned by GRE. The restrictions described in the PSC’s order, which were to become effective March 4, 2016, would require that all REPs’ electricity and natural gas offerings to residential and small business customers include an annual guarantee of savings compared to the price charged by the relevant incumbent utility or, for electricity offerings, provide at least 30% of the supply from renewable sources. Customers not enrolled in a compliant program would be relinquished back to the local utility at the end of their contract period or, for variable price customers operating on month to month agreements, at the end of the current monthly billing cycle. On March 4, 2016, a group of parties from the REP industry sought and won a temporary restraining order to stay implementation of the most restrictive portions of the PSC’s order pending a court hearing on those parties’ motion for a preliminary injunction. On July 25, 2016, the New York State Supreme Court, County of Albany, entered a decision and order granting the Petitioners’ petition, vacated provisions 1 through 3 of the Order, and remitted the matter to the PSC for further proceedings consistent with the Court’s order. In December 2017, the PSC held an evidentiary hearing to assess the retail energy market in New York. That process is continuing and is expected to last for at least several more months. The Company is evaluating the potential impact of any new order from the PSC that would follow from the evidentiary process, while preparing to operate in compliance with any new requirements that may be imposed. Depending on the final language of any new order, as well as the Company’s ability to modify its relationships with its New York customers, an order could have a substantial impact upon the operations of GRE’s REPs in New York. At December 31, 2017, New York represented 36% of GRE’s total meters served and 28% of the total residential customer equivalents (“RCEs”) of GRE’s customer base. On July 14, 2016, and September 19, 2016, the PSC issued orders restricting REPs, including those owned by GRE, from serving customers enrolled in New York’s utility low-income assistance programs. Representatives of the REP industry challenged the ruling in New York State Supreme Court, Albany County, and, on September 27, 2016, the Court issued an order temporarily restraining the PSC from implementing the July and September orders. On December 16, 2016, the PSC issued an order (the “2016 Order”) prohibiting REP service to customers enrolled in New York’s utility low-income assistance programs. After an agreed-upon delay, on July 5, 2017, the New York State Supreme Court, Albany County, denied interested parties’ efforts to invalidate the 2016 Order, and the 2016 Order began to be implemented on July 26, 2017. Several REPs have appealed the Supreme Court’s Order to the Appellate Division, Third Department. That court stayed implementation of the 2016 Order for a period of time, but later lifted the stay pending resolution of the appeal. In a related action, several customers impacted by the 2016 Order filed a putative class action in the United States District Court for the Northern District of New York, challenging the 2016 Order. Temporary stays of the 2016 Order entered in connection with this action have expired, and REPs are now required to return service of their current low-income customers to the relevant local incumbent utility on the modified schedule set forth in the PSC’s 2016 Order. GRE’s REPs are complying with the 2016 Order and have begun the transfer of customers as required. The 2016 Order will require GRE’s REPs to transfer customer accounts comprising approximately 21,000 meters, representing 12,000 RCEs, to their respective incumbent utilities during the first half of 2018.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Note 16 — Commitments and Contingencies Purchase Commitments The Company had purchase commitments of $46.4 million at December 31, 2017, of which $45.0 million was for future purchases of electricity. The purchase commitments outstanding at December 31, 2017 are expected to be paid as follows: $43.2 million in the year ending December 31, 2018, and $3.2 million in the year ending December 31, 2019. Renewable Energy Credits GRE must obtain a certain percentage or amount of its power supply from renewable energy sources in order to meet the requirements of renewable portfolio standards in the states in which it operates. This requirement may be met by obtaining renewable energy credits that provide evidence that electricity has been generated by a qualifying renewable facility or resource. At December 31, 2017, GRE had commitments to purchase renewable energy credits of $15.6 million. Performance Bonds GRE has performance bonds issued through a third party for certain utility companies and for the benefit of various states in order to comply with the states’ financial requirements for REPs. At December 31, 2017, GRE had aggregate performance bonds of $11.8 million outstanding. Lease Commitments The future minimum payments for operating leases at December 31, 2017 are as follows: (in thousands) Year ending December 31: 2018 $ 193 2019 77 2020 41 2021 — 2022 — Thereafter — Total payments $ 311 Rental expense under operating leases was $0.8 million, $0.7 million and $1.2 million in the years ended December 31, 2017, 2016 and 2015, respectively. BP Energy Company Preferred Supplier Agreement As of November 19, 2015, IDT Energy and certain of its affiliates entered into an Amended and Restated Preferred Supplier Agreement with BP Energy Company (“BP”). The agreement’s termination date is November 30, 2019, except either party may terminate the agreement on November 30, 2018 by giving the other party notice by May 31, 2018. Under the agreement, IDT Energy purchases electricity and natural gas at market rate plus a fee. IDT Energy’s obligations to BP are secured by a first security interest in deposits or receivables from utilities in connection with their purchase of IDT Energy’s customer’s receivables, and in any cash deposits or letters of credit posted in connection with any collateral accounts with BP. IDT Energy’s ability to purchase electricity and natural gas under this agreement is subject to satisfaction of certain conditions including the maintenance of certain covenants. At December 31, 2017, the Company was in compliance with such covenants. At December 31, 2017, restricted cash — short-term of $0.5 million and trade accounts receivable of $34.4 million were pledged to BP as collateral for the payment of IDT Energy’s trade accounts payable to BP of $13.8 million at December 31, 2017.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Note 17 — Related Party Transactions The Company was formerly a subsidiary of IDT Corporation (“IDT”). On October 28, 2011, the Company was spun-off by IDT and became an independent public company through a pro rata distribution of the Company’s common stock to IDT’s stockholders (the “Spin-Off”). The Company entered into various agreements with IDT prior to the Spin-Off including a Separation and Distribution Agreement to effect the separation and provide a framework for the Company’s relationship with IDT after the Spin-Off, and a Transition Services Agreement, which provides for certain services to be performed by the Company and IDT. IDT charges the Company for services it provides pursuant to the Transition Services Agreement. The charges for these services are included in “Selling, general and administrative” expense. In addition, the Company provides services to certain of IDT’s subsidiaries. The charges for these services reduce the Company’s “Selling, general and administrative” expense. Year ended December 31, (in thousands) 2017 2016 2015 Amount IDT charged the Company $ 1,773 $ 2,197 $ 2,340 Amount the Company charged IDT 471 627 546 The Company had notes receivable outstanding from employees aggregating $0.6 million and $1.0 million at December 31, 2017 and 2016, respectively, which were included in “Other assets” in the accompanying consolidated balance sheet. The Company obtains insurance policies from several insurance brokers, one of which is IGM Brokerage Corp. (“IGM”). IGM is owned by the mother of Howard S. Jonas and Joyce Mason, the Company’s Corporate Secretary. Jonathan Mason, husband of Joyce Mason and brother-in-law of Howard S. Jonas, provides insurance brokerage services via IGM. Based on information the Company received from IGM, the Company believes that (1) IGM received commissions and fees from payments made by the Company (including payments from third party brokers) in the aggregate amounts of $20,060; $18,164 and $14,236 in the years ended December 31, 2017, 2016 and 2015, respectively, which fees and commissions inured to the benefit of Mr. Mason, and (2) the total payments made by the Company to IGM for various insurance policies were $20,060; $18,657 and $143,367 in the years ended December 31, 2017, 2016 and 2015, respectively. The commissions and fees paid to IGM in the years ended December 31, 2017 and 2016 included commissions and fees for various insurance policies for which the Company paid $201,565 and $144,110, respectively, to a third party broker. Neither Howard S. Jonas nor Joyce Mason has any ownership or other interest in IGM other than via the familial relationships with their mother and Jonathan Mason.

Business Segment and Geographic

Business Segment and Geographic Information	12 Months Ended
	Dec. 31, 2017
Business Segment and Geographic Information [Abstract]
Business Segment and Geographic Information	Note 18 — Business Segment and Geographic Information The Company owns 99.3% of its subsidiary, GEIC, which owns 100% of GRE and 92% of GOGAS. The Company has three reportable business segments: GRE, Afek and GOGAS. GRE owns and operates REPs, including IDT Energy, Residents Energy, Town Square Energy, and Mirabito, and also offers energy brokerage and advisory services. Its REP businesses resell electricity and natural gas to residential and small business customers in the Eastern and Midwestern United States. GRE has outstanding deferred stock units granted to officers and employees that represent an interest of 1.25% of the equity of GRE. The Afek segment is comprised of the Company’s 86.1% interest in Afek, an oil and gas exploration project in the Golan Heights in Northern Israel, whose operations have been suspended. The GOGAS segment is comprised of inactive oil shale projects including AMSO, LLC, Genie Mongolia and IEI. Corporate costs include unallocated compensation, consulting fees, legal fees, business development expenses and other corporate-related general and administrative expenses. Corporate does not generate any revenues, nor does it incur any cost of revenues. The Company’s reportable segments are distinguished by types of service, customers and methods used to provide their services. The operating results of these business segments are regularly reviewed by the Company’s chief operating decision maker. The accounting policies of the segments are the same as the accounting policies of the Company as a whole. The Company evaluates the performance of its business segments based primarily on income (loss) from operations. There are no significant asymmetrical allocations to segments. Operating results for the business segments of the Company were as follows: (in thousands) GRE Afek GOGAS Corporate Total Year ended December 31, 2017 Revenues $ 264,202 $ — $ — $ — $ 264,202 Income (loss) from operations 16,586 (12,698 ) (593 ) (9,835 ) (6,540 ) Depreciation and amortization 1,740 327 72 1 2,140 Exploration — 4,879 — — 4,879 Write-off of capitalized exploration costs — 6,483 — — 6,483 Equity in the net loss of Shoreditch 565 — — — 565 Year ended December 31, 2016 Revenues $ 212,112 $ — $ — $ — $ 212,112 Income (loss) from operations 26,503 (48,272 ) 439 (9,183 ) (30,513 ) Depreciation and amortization 427 124 29 1 581 Research and development — — (269 ) — (269 ) Exploration — 6,088 — — 6,088 Write-off of capitalized exploration costs — 41,041 — — 41,041 Equity in the net loss of AMSO, LLC — — 222 — 222 Year ended December 31, 2015 Revenues $ 213,056 $ — $ — $ — $ 213,056 Income (loss) from operations 11,095 (7,458 ) (3,058 ) (8,908 ) (8,329 ) Depreciation 245 104 78 1 428 Research and development — 63 1,922 — 1,985 Exploration — 6,583 — — 6,583 Equity in the net loss of AMSO, LLC — — 397 — 397 Total assets for the business segments of the Company were as follows: (in thousands) GRE Afek GOGAS Corporate Total Total assets: December 31, 2017 $ 112,521 $ 2,588 $ 7,887 $ 2,782 $ 125,778 December 31, 2016 87,539 6,685 12,224 15,365 121,813 December 31, 2015 80,177 38,665 17,770 19,203 155,815 Geographic Information There were no revenues from customers located outside of the United States in all periods presented. Net long-lived assets and total assets held outside of the United States, which are located primarily in Israel, were as follows: (in thousands) United Foreign Countries Total December 31, 2017 Long-lived assets, net $ 696 $ 3,352 $ 4,048 Total assets 115,605 10,173 125,778 December 31, 2016 Long-lived assets, net $ 1,060 $ 582 $ 1,642 Total assets 113,158 8,655 121,813 December 31, 2015 Long-lived assets, net $ 763 $ 646 $ 1,409 Total assets 114,880 40,935 155,815

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2017
Selected Quarterly Financial Data (Unaudited) [Abstract]
Selected Quarterly Financial Data (Unaudited)	Note 19 — Selected Quarterly Financial Data (Unaudited) The table below presents selected quarterly financial data of the Company for its fiscal quarters in 2017 and 2016. The financial data for the three months ended March 31, 2017 and June 30, 2017 in the table below reflects the restatements in 2017. Quarter Ended Income (loss) Net income (loss) attributable (Loss) earnings per (in thousands, except per share data) Revenues Cost of revenues from operations Net (loss) income to Genie Energy Ltd. Basic Diluted 2017: December 31 (1) $ 73,077 $ 46,321 $ 430 $ (812 ) $ 215 $ (0.01 ) $ (0.01 ) September 30 (2) 69,473 47,694 1,403 975 778 0.02 0.02 June 30 (3) 50,247 38,122 (13,569 ) (12,950 ) (12,569 ) (0.55 ) (0.55 ) March 31 71,405 46,556 5,196 4,139 4,582 0.18 0.18 TOTAL $ 264,202 $ 178,693 $ (6,540 ) $ (8,648 ) $ (6,994 ) $ (0.36 ) $ (0.36 ) 2016: December 31 $ 51,519 $ 36,949 $ (1,344 ) $ (1,285 ) $ (816 ) $ (0.05 ) $ (0.05 ) September 30 (1) 57,153 36,946 (37,102 ) (37,174 ) (32,139 ) (1.43 ) (1.43 ) June 30 44,561 26,445 1,934 1,417 2,761 0.10 0.10 March 31 58,879 34,832 5,999 4,850 5,669 0.23 0.22 TOTAL $ 212,112 $ 135,172 $ (30,513 ) $ (32,192 ) $ (24,525 ) $ (1.14 ) $ (1.14 ) (1) In the fourth quarter of 2017 and in the third quarter of 2016, loss from operations included write-off of capitalized exploration costs of $6.5 million and $41.0 million, respectively. (2) In the third quarter of 2017, the Company recognized a liability of $1.5 million for a tentative agreement in principle with the New Jersey Office of the Attorney General regarding concerns related to energy supply charges issued to our retail customers during the first quarter of 2014. The Company recorded the liability as a revenue reduction of $1.3 million and an expense of $0.2 million. (3) In the second quarter of 2017, the Company recognized a liability of $9.0 million for the preliminary settlement of certain class action lawsuits. The Company recorded the liability as a revenue reduction of $3.6 million and an expense of $5.4 million.

Description of Business and S29

Description of Business and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Description of Business and Summary of Significant Accounting Policies [Abstract]
Description of Business	Description of Business Genie Energy Ltd. (“Genie”), a Delaware corporation, was incorporated in January 2011. Genie owns 99.3% of its subsidiary, Genie Energy International Corporation (“GEIC”), which owns 100% of Genie Retail Energy (“GRE”) and 92% of Genie Oil and Gas, Inc. (“GOGAS”). The “Company” in these financial statements refers to Genie, Genie Retail Energy and Genie Oil and Gas, and their respective subsidiaries, on a consolidated basis. Genie 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 in the Eastern and Midwestern United States. Genie is also comprised of Genie Oil and Gas, 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, whose operations have been suspended. GOGAS also holds controlling interests in other inactive oil and gas projects. GRE has outstanding deferred stock units granted to officers and employees that represent an interest of 1.25% of the equity of GRE.
Basis of Consolidation	Basis of Consolidation The method of accounting applied to long-term investments, whether consolidated, equity or cost, involves an evaluation of the significant terms of each investment that explicitly grant or suggest evidence of control or influence over the operations of the investee and also includes the identification of any variable interests in which the Company is the primary beneficiary. The consolidated financial statements include the Company’s controlled subsidiaries and the variable interest entity in which the Company is the primary beneficiary (see Note 13). All significant intercompany accounts and transactions between the consolidated entities are eliminated.
Accounting for Investments	Accounting for Investments Investments in businesses that the Company does not control, but in which the Company has the ability to exercise significant influence over operating and financial matters, are accounted for using the equity method. The Company periodically evaluates its equity method investments for impairment due to declines considered to be other than temporary. If the Company determines that a decline in fair value is other than temporary, then a charge to earnings is recorded, and a new basis in the investment is established.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates.
Revenue Recognition	Revenue Recognition Revenues from GRE’s sale of electricity and natural gas are recognized under the accrual method based on deliveries of electricity and natural gas to customers. Revenues from electricity and natural gas delivered but not billed are estimated and recorded as accounts receivable. Cash received in advance from customers under billing arrangement is reported as deferred revenue and is included in “Accrued expenses” in the accompanying consolidated balance sheets. GOGAS does not yet generate revenues. In May 2014, the Financial Accounting Standards Board (“FASB”) and the International Accounting Standards Board jointly issued a comprehensive new revenue recognition standard that superseded most of the revenue recognition guidance under U.S. GAAP and International Financial Reporting Standards (“IFRS”). The goals of the revenue recognition project were to clarify and converge the revenue recognition principles under U.S. GAAP and IFRS and to develop guidance that would streamline and enhance revenue recognition requirements. The Company adopted this standard on January 1, 2018 using the modified retrospective method. The Company has substantially completed its evaluation of the effects of adopting the new standard and determined that it will not have any impact on revenue recognition and measurement in its consolidated financial statements upon adoption. Variable quantities in requirements contracts are considered to be options for additional goods and services which follow discussions outlined in the AICPA Power and Utilities Industry Task Force Issue No. 13-2. Revenue for each unit of electricity or natural gas is recognized as it is delivered to the customer. The Company will estimate variable consideration related to its rebate programs using the expected value method and a portfolio approach. The Company expects to apply a practical expedient for expensing costs to obtain a contract as the estimated customer relationship periods are currently less than twelve months. The Company will monitor its customer relationship periods going forward to ensure compliance with the application of the practical expedient. The adoption of the new standard will not have any impact on the Company’s current method of recording accrued rebates. The Company is also currently reviewing future required disclosures, and updating its accounting policy. The Company anticipates completing the implementation in connection with its first quarter 2018 interim financial statements.
Cost of Revenues	Cost of Revenues Cost of revenues for GRE consists primarily of the cost of natural gas and electricity sold, and also includes financing fees, scheduling costs, Independent System Operator (“ISO”) fees, pipeline costs and utility service charges. In addition, the changes in the fair value of GRE’s futures contracts, swaps and put and call options are recorded in cost of revenues. GOGAS does not yet incur cost of revenues.
Research and Development Costs	Research and Development Costs Research and development costs are charged to expense as incurred.
Oil and Gas Exploration Costs	Oil and Gas Exploration Costs The Company accounts for its oil and gas activities under the successful efforts method of accounting. Under this method, the costs of drilling exploratory wells and exploratory-type stratigraphic test wells are capitalized, pending determination of whether the well has found proved reserves. Other exploration costs are charged to expense as incurred. Unproved properties are assessed for impairment, and if considered impaired, are charged to expense when such impairment is deemed to have occurred (see Note 5).
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with an original maturity of three months or less when purchased to be cash equivalents.
Inventory	Inventory Inventory consists of natural gas, which is stored at various third parties’ underground storage facilities, of $1.0 million and $0.6 million at December 31, 2017 and 2016, respectively. Inventory also includes renewable energy credits of $3.0 million and $5.4 million at December 31, 2017 and 2016, respectively. On January 1, 2017, the Company adopted the Accounting Standards Update (“ASU”) that changed the measurement of its natural gas inventory to the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. The adoption of this ASU did not have a significant impact on the Company’s consolidated financial statements. Prior to January 1, 2017, the Company’s natural gas inventory was valued at weighted average cost, which was based on the purchase price of the natural gas and the cost to transport, plus or minus injections or withdrawals.
Renewable Energy Credits	Renewable Energy Credits GRE must obtain a certain percentage or amount of its power supply from renewable energy sources in order to meet the requirements of renewable portfolio standards in the states in which it operates. This requirement may be met by obtaining renewable energy credits that provide evidence that electricity has been generated by a qualifying renewable facility or resource. GRE holds renewable energy credits for both sale and use, and treats the credits as a government incentive to encourage the construction of renewable power plants. Renewable energy credits are valued at the lower of cost and market, where cost is the purchase price. Gains and losses from the sale of renewable energy credits are recognized in cost of revenues when the credits are transferred to the buyer.
Long-Lived Assets	Long-Lived Assets Computer software and development, computers and computer hardware, laboratory and drilling equipment and office equipment and other are recorded at cost and are depreciated on a straight-line basis over their estimated useful lives, which range as follows: computer software and development — 2, 3 or 5 years; computers and computer hardware — 5 years, laboratory and drilling equipment — 7 years, and office equipment and other —5 or 7 years. Leasehold improvements included in office equipment and other are recorded at cost and are depreciated on a straight-line basis over the term of their lease or their estimated useful lives, whichever is shorter. The fair value of patents and trademarks, non-compete agreements and customer relationships acquired in a business combination accounted for under the purchase method are amortized over their estimated useful lives as follows: patents and trademarks are amortized on a straight-line basis over the 20-year period of expected cash flows; non-compete agreements are amortized on a straight-line basis over their 2 year term; and customer relationships are amortized ratably over the 2 or 9 year period of expected cash flows. The Company tests the recoverability of its long-lived assets with finite useful lives whenever events or changes in circumstances indicate that the carrying value of the asset may not be recoverable. The Company tests the recoverability based on the projected undiscounted cash flows to be derived from such asset. If the projected undiscounted future cash flows are less than the carrying value of the asset, the Company will record an impairment loss based on the difference between the estimated fair value and the carrying value of the asset. The Company generally measures fair value by considering sale prices for similar assets or by discounting estimated future cash flows from such asset using an appropriate discount rate. Cash flow projections and fair value estimates require significant estimates and assumptions by management. Should the estimates and assumptions prove to be incorrect, the Company may be required to record impairments in future periods and such impairments could be material.
Goodwill and Indefinite Lived Intangible Assets	Goodwill and Indefinite Lived Intangible Assets Goodwill is the excess of the acquisition cost of businesses over the fair value of the identifiable net assets acquired. Goodwill and other indefinite lived intangible assets are not amortized. These assets are reviewed annually (or more frequently under various conditions) for impairment using a fair value approach. In 2017, the Company adopted the ASU that simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. In computing the implied fair value of goodwill under Step 2, an entity had to perform procedures to determine the fair value at the impairment testing date of its assets and liabilities (including unrecognized assets and liabilities) following the procedure that would be required in determining the fair value of assets acquired and liabilities assumed in a business combination. Instead, under the amendments in this ASU, the Company performs its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. The Company would recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized would not exceed the total amount of goodwill allocated to that reporting unit. Additionally, the Company considers income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit when measuring the goodwill impairment loss, if applicable. The fair value of the reporting unit is estimated using discounted cash flow methodologies, as well as considering third party market value indicators. Calculating the fair value of the reporting units requires significant estimates and assumptions by management. Should the estimates and assumptions regarding the fair value of the reporting units prove to be incorrect, the Company may be required to record impairments to its goodwill in future periods and such impairments could be material. The Company has the option to perform a qualitative assessment to determine whether it is necessary to perform the quantitative goodwill impairment test. However, the Company may elect to perform the quantitative goodwill impairment test even if no indications of a potential impairment exist. For the impairment test of the Company’s indefinite-lived intangible assets, a quantitative impairment test is only necessary if the Company determines that it is more likely than not that an indefinite-lived intangible asset is impaired based on an assessment of certain qualitative factors.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities The Company records its derivatives instruments at their respective fair values. The accounting for changes in the fair value (that is, gains or losses) of a derivative instrument is dependent upon whether the derivative has been designated and qualifies as part of a hedging relationship and further, on the type of hedging relationship. Due to the volatility of electricity and natural gas prices, GRE enters into futures contracts, swaps and put and call options as hedges against unfavorable fluctuations in market prices of electricity and natural gas and to reduce exposure from price fluctuations. The Company does not designate its derivative instruments to qualify for hedge accounting, accordingly the futures contracts, swaps and put and call options are recorded at fair value as a current asset or liability and any changes in fair value are recorded in “Cost of revenues” in the consolidated statements of operations. In addition to the above, GRE utilizes forward physical delivery contracts for a portion of its purchases of electricity and natural gas, which are defined as commodity derivative contracts. Using the exemption available for qualifying contracts, GRE applies the normal purchase and normal sale accounting treatment to its forward physical delivery contracts, thereby these contracts are not adjusted to fair value. GRE also applies the normal purchase and normal sale accounting treatment to forward contracts for the physical delivery of electricity in nodal energy markets that result in locational marginal pricing charges or credits, since this does not constitute a net settlement, even when legal title to the electricity is conveyed to the ISO during transmission. Accordingly, GRE recognizes revenue from customer sales, and the related cost of revenues, at the contracted price, as electricity and natural gas is delivered to retail customers.
Repairs and Maintenance	Repairs and Maintenance The Company charges the cost of repairs and maintenance, including the cost of replacing minor items not constituting substantial betterment, to selling, general and administrative expense as these costs are incurred.
Foreign Currency Translation	Foreign Currency Translation Assets and liabilities of foreign subsidiaries denominated in foreign currencies are translated to U.S. Dollars at end-of-period rates of exchange, and their monthly results of operations are translated to U.S. Dollars at the average rates of exchange for that month. Gains or losses resulting from such foreign currency translations are recorded in “Accumulated other comprehensive income” in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are reported in “Other (expense) income, net” in the accompanying consolidated statements of operations.
Advertising Expense	Advertising Expense Cost of advertising for customer acquisitions are charged to selling, general and administrative expense in the period in which it is incurred. Most of the advertisements are in print, over the radio, or direct mail. In the years ended December 31, 2017, 2016 and 2015, advertising expense included in selling, general and administrative expense was $2.1 million, $1.4 million and $0.9 million, respectively.
Income Taxes	Income Taxes The Company recognizes deferred tax assets and liabilities for the future tax consequences attributable to temporary differences between the financial statements carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is provided when it is more likely than not that some portion or all of a deferred tax asset will not be realized. The ultimate realization of deferred tax assets depends on the generation of future taxable income during the period in which related temporary differences become deductible. The Company considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in its assessment of a valuation allowance. Deferred tax assets and liabilities are measured using the enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date of such change. The Company uses a two-step approach for recognizing and measuring tax benefits taken or expected to be taken in a tax return. The Company determines whether it is more-likely-than-not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. In evaluating whether a tax position has met the more-likely-than-not recognition threshold, the Company presumes that the position will be examined by the appropriate taxing authority that has full knowledge of all relevant information. Tax positions that meet the more-likely-than-not recognition threshold are measured to determine the amount of tax benefit to recognize in the financial statements. The tax position is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon ultimate settlement. Differences between tax positions taken in a tax return and amounts recognized in the financial statements will generally result in one or more of the following: an increase in a liability for income taxes payable, a reduction of an income tax refund receivable, a reduction in a deferred tax asset, or an increase in a deferred tax liability. The Company classifies interest and penalties on income taxes as a component of income tax expense.
Contingencies	Contingencies The Company accrues for loss contingencies when both (a) information available prior to issuance of the financial statements indicates that it is probable that a liability had been incurred at the date of the financial statements and (b) the amount of loss can reasonably be estimated. When the Company accrues for loss contingencies and the reasonable estimate of the loss is within a range, the Company records its best estimate within the range. When no amount within the range is a better estimate than any other amount, the Company accrues the minimum amount in the range. The Company discloses an estimated possible loss or a range of loss when it is at least reasonably possible that a loss may have been incurred.
Earnings Per Share	Earnings Per Share Basic earnings per share is computed by dividing net income or loss attributable to all classes of common stockholders of the Company by the weighted average number of shares of all classes of common stock outstanding during the applicable period. Diluted earnings per share is determined in the same manner as basic earnings per share, except that the number of shares is increased to include restricted stock still subject to risk of forfeiture and to assume exercise of potentially dilutive stock options using the treasury stock method, unless the effect of such increase is anti-dilutive. The following shares were excluded from the diluted earnings per share computations because their inclusion would have been anti-dilutive: Year ended December 31, (in thousands) 2017 2016 2015 Stock options 383 414 414 Non-vested restricted Class B common stock 762 1,226 1,852 Shares excluded from the calculation of diluted earnings per share 1,145 1,640 2,266 The diluted loss per share equals basic loss per share in the years ended December 31, 2017, 2016 and 2015 because the Company had a net loss and the impact of the assumed exercise of stock options and vesting of restricted stock would have been anti-dilutive. In March 2018, the Company and an entity affiliated with Lord (Jacob) Rothschild agreed in principle that the Rothschild’s entity will exercise its option to exchange its 5% equity interest in GOGAS for Class B shares of the Company’s common stock with a fair value of $0.2 million. Employees and directors of the Company that were previously granted restricted stock of Afek and Genie Mongolia, Inc. (“Genie Mongolia”) have the right to exchange the restricted stock, upon vesting of such shares, into shares of the Company’s Class B common stock. GRE has the right, at its option, to satisfy its obligations to issue common stock of GRE upon the vesting of the deferred stock units it granted in July 2015 to officers and employees of the Company in shares of the Company’s Class B common stock or cash. These exchanges and issuances, if elected, would be based on the relative fair value of the shares exchanged or to be issued. The number of shares of the Company’s stock issuable in an exchange is not currently determinable. If shares of the Company’s stock are issued upon such exchange, the Company’s earnings per share may be diluted in future periods.
Stock-Based Compensation	Stock-Based Compensation The Company recognizes compensation expense for grants of stock-based awards to its employees based on the estimated fair value on the grant date. Stock based awards granted to nonemployees are marked-to-market until the vesting of the award. Compensation cost for awards is recognized using the straight-line method over the requisite service period, which approximates the vesting period. Stock-based compensation is included in selling, general and administrative expense.
Vulnerability Due to Certain Concentrations	Vulnerability Due to Certain Concentrations Financial instruments that potentially subject the Company to concentration of credit risk consist principally of cash, cash equivalents, restricted cash, certificates of deposit and trade accounts receivable. The Company holds cash, cash equivalents, restricted cash and certificates of deposit at several major financial institutions, which may exceed FDIC insured limits. Historically, the Company has not experienced any losses due to such concentration of credit risk. The Company’s temporary cash investments policy is to limit the dollar amount of investments with any one financial institution and monitor the credit ratings of those institutions. While the Company may be exposed to credit losses due to the nonperformance of the holders of its deposits, the Company does not expect the settlement of these transactions to have a material effect on its results of operations, cash flows or financial condition. GRE’s REPs reduce their customer credit risk by participating in purchase of receivable programs for a majority of their receivables. In addition to providing billing and collection services, utility companies purchase those REPs’ receivables and assume all credit risk without recourse to those REPs. GRE’s REPs’ primary credit risk is therefore nonpayment by the utility companies. Certain of the utility companies represent significant portions of the Company’s consolidated revenues and consolidated gross trade accounts receivable balance and such concentrations increase the Company’s risk associated with nonpayment by those utility companies. The following table summarizes the percentage of consolidated revenues from customers by utility company that equal or exceed 10% of consolidated revenues in the period (no other single utility company accounted for more than 10% of consolidated revenues in these periods): Year ended December 31, 2017 2016 2015 Con Edison 15 % 20 % 23 % ComEd 10 % 13 % na National Grid USA na na 12 % na – less than 10% of consolidated revenue in the period The following table summarizes the percentage of consolidated gross trade accounts receivable by utility company that equal or exceed 10% of consolidated gross trade accounts receivable at December 31, 2017 and 2016 (no other single utility company accounted for 10% or greater of the Company’s consolidated gross trade accounts receivable at December 31, 2017 or 2016): December 31 2017 2016 Con Edison 11 % 15 % ComEd na 10 % na – less than 10% of consolidated gross trade accounts receivable
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The allowance for doubtful accounts reflects the Company’s best estimate of probable losses inherent in the accounts receivable balance. The allowance is determined based on known troubled accounts, historical experience and other currently available evidence. Doubtful accounts are written-off upon final determination that the trade accounts will not be collected. The change in the allowance for doubtful accounts was as follows: (in thousands) Balance at beginning of period Additions charged (reversals credited) to expense Additions (deductions) (1) Balance at end of period Year ended December 31, 2017 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 171 $ 762 $ 166 $ 1,099 Year ended December 31, 2016 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 182 $ 8 $ (19 ) $ 171 Year ended December 31, 2015 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 227 $ (29 ) $ (16 ) $ 182 (1) Primarily uncollectible accounts written off, net of recoveries.
Fair Value Measurements	Fair Value Measurements Fair value of financial and non-financial assets and liabilities is defined as an exit price, which is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The three-tier hierarchy for inputs used to measure fair value, which prioritizes the inputs to valuation techniques used to measure fair value, is as follows: Level 1 — quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 — quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 — unobservable inputs based on the Company’s assumptions used to measure assets and liabilities at fair value. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of the assets and liabilities being measured and their placement within the fair value hierarchy.
Accounting Standards Updates	Accounting Standards Updates In January 2016, the FASB issued an ASU to provide more information about recognition, measurement, presentation and disclosure of financial instruments. The amendments in the ASU include, among other changes, the following: (1) equity investments (except those accounted for under the equity method or that result in consolidation) will be measured at fair value with changes in fair value recognized in net income, (2) a qualitative assessment each reporting period to identify impairment of equity investments without readily determinable fair values, (3) financial assets and financial liabilities will be presented separately by measurement category and form of financial asset on the balance sheet or the notes to the financial statements, and (4) an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. Entities will no longer be able to recognize unrealized holding gains and losses on equity securities classified as available-for-sale in other comprehensive income. In addition, a practicability exception will be available for equity investments that do not have readily determinable fair values and do not qualify for the net asset value practical expedient. These investments may be measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for an identical or similar investment of the same issuer. Entities will have to reassess at each reporting period whether an investment qualifies for this practicability exception. The Company adopted the amendments in this ASU on January 1, 2018. This ASU did not have a significant impact on the Company’s consolidated financial statements. In February 2016, the FASB issued an ASU related to the accounting for leases. The new standard establishes a right-of-use (“ROU”) model that requires a lessee to record a ROU asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. The Company will adopt the new standard on January 1, 2019. A modified retrospective transition approach is required for lessees for capital and operating leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements, with certain practical expedients available. The Company is evaluating the impact that the new standard will have on its consolidated financial statements. In June 2016, the FASB issued an ASU that changes the impairment model for most financial assets and certain other instruments. For receivables, loans and other instruments, entities will be required to use a new forward-looking “expected loss” model that generally will result in the earlier recognition of allowance for losses. For available-for-sale debt securities with unrealized losses, entities will measure credit losses in a manner similar to current practice, except the losses will be recognized as allowances instead of reductions in the amortized cost of the securities. In addition, an entity will have to disclose significantly more information about allowances, credit quality indicators and past due securities. The new provisions will be applied as a cumulative-effect adjustment to retained earnings. The Company will adopt the new standard on January 1, 2020. The Company is evaluating the impact that the new standard will have on its consolidated financial statements. In November 2016, the FASB issued an ASU that includes specific guidance on the classification and presentation of changes in restricted cash and cash equivalents in the statement of cash flows. The amendments in this ASU require that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Amounts generally described as restricted cash or restricted cash equivalents will be included with cash and cash equivalents when reconciling the beginning of the period and end of the period total amounts shown on the statement of cash flows. The ASU will be applied using a retrospective transition method to each period presented. The Company adopted the amendments in this ASU on January 1, 2018. Beginning in the first quarter of 2018, the adoption will impact the Company’s beginning of the period and end of the period cash and cash equivalents balance in its statement of cash flows, as well as its net cash provided by operating and financing activities. In January 2017, the FASB issued an ASU to clarify the definition of a business with the objective of adding guidance to assist entities with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. Under the current guidance, there are three elements of a business—inputs, processes, and outputs. While an integrated set of assets and activities (collectively referred to as a “set”) that is a business usually has outputs, outputs are not required to be present. In addition, all the inputs and processes that a seller uses in operating a set are not required if market participants can acquire the set and continue to produce outputs, for example, by integrating the acquired set with their own inputs and processes. The amendments in this ASU provide a screen to determine when a set is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or a group of similar identifiable assets, the set is not a business. This screen reduces the number of transactions that need to be further evaluated. If the screen is not met, the amendments in this ASU (1) require that to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output and (2) remove the evaluation of whether a market participant could replace missing elements. The amendments provide a framework to assist entities in evaluating whether both an input and a substantive process are present. The framework includes two sets of criteria to consider that depend on whether a set has outputs. Although outputs are not required for a set to be a business, outputs generally are a key element of a business; therefore, the FASB has developed more stringent criteria for sets without outputs. Lastly, the ASU narrows the definition of the term output. The Company adopted the amendments in this ASU on January 1, 2018. The adoption will impact the Company’s accounting for acquisitions and disposals of assets or businesses on a prospective basis; however, there was no impact on the Company’s historical consolidated financial statements. In August 2017, the FASB issued an ASU intended to improve the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. In addition, the ASU includes certain targeted improvements to simplify the application of hedge accounting guidance in U.S. GAAP. The amendments in this ASU are effective for the Company on January 1, 2019. Early application is permitted. Entities will apply the amendments to cash flow and net investment hedge relationships that exist on the date of adoption using a modified retrospective approach. The presentation and disclosure requirements will be applied prospectively. The Company is evaluating the impact that this ASU will have on its consolidated financial statements.

Description of Business and S30

Description of Business and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2017
Description of Business and Summary of Significant Accounting Policies [Abstract]
Schedule of antidilutive shares were excluded from the diluted earnings per share computations	Year ended December 31, (in thousands) 2017 2016 2015 Stock options 383 414 414 Non-vested restricted Class B common stock 762 1,226 1,852 Shares excluded from the calculation of diluted earnings per share 1,145 1,640 2,266
Schedule of percentage of consolidated revenues from customers by utility company and percentage of consolidated gross trade accounts receivable by utility company	Year ended December 31, 2017 2016 2015 Con Edison 15 % 20 % 23 % ComEd 10 % 13 % na National Grid USA na na 12 % na – less than 10% of consolidated revenue in the period December 31 2017 2016 Con Edison 11 % 15 % ComEd na 10 % na – less than 10% of consolidated gross trade accounts receivable
Schedule of change in allowance for doubtful accounts	(in thousands) Balance at beginning of period Additions charged (reversals credited) to expense Additions (deductions) (1) Balance at end of period Year ended December 31, 2017 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 171 $ 762 $ 166 $ 1,099 Year ended December 31, 2016 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 182 $ 8 $ (19 ) $ 171 Year ended December 31, 2015 Reserves deducted from accounts receivable: Allowance for doubtful accounts $ 227 $ (29 ) $ (16 ) $ 182 (1) Primarily uncollectible accounts written off, net of recoveries.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Retail Energy Holdings, LLC [Member]
Business Acquisition [Line Items]
Schedule of acquisition's purchase price allocations	(in thousands) Trade accounts receivable $ 3,614 Inventory 287 Prepaid expenses 81 Other current assets 26 Property and equipment 110 Trademark 2,100 Non-compete agreement 110 Customer relationships (2-year useful life) 2,100 Goodwill 5,065 Other assets 1,600 Revolving line of credit (1,919 ) Trade accounts payable (2,620 ) Accrued expenses (1,542 ) Net assets excluding cash acquired $ 9,012 Supplemental information: Cash paid $ 10,949 Cash acquired (2,249 ) Cash paid, net of cash acquired 8,700 Liability for additional purchase price (paid in 2017) 312 Total consideration, net of cash acquired $ 9,012
Schedule of pro forma information	Year ended December 31, (in thousands) 2016 2015 Revenues $ 243,147 $ 243,165 Net loss $ (32,303 ) $ (11,256 )
Mirabito Natural Gas [Member]
Business Acquisition [Line Items]
Schedule of acquisition's purchase price allocations	(in thousands) Trade accounts receivable $ 509 Prepaid expenses 60 Non-compete agreement 5 Customer relationships (9-year useful life) 1,100 Patents and trademarks 760 Goodwill 1,270 Other assets 465 Trade accounts payable (299 ) Accrued expenses (2 ) Net assets excluding cash acquired $ 3,868 Supplemental information: Cash paid $ 3,955 Cash acquired (87 ) Total consideration, net of cash acquired $ 3,868
Schedule of pro forma information	Year ended December 31, (in thousands) 2017 2016 Revenues $ 268,008 $ 217,448 Net loss $ (8,588 ) $ (32,031 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Measurements [Abstract]
Schedule of balance of assets and liabilities measured at fair value on a recurring basis	(in thousands) Level 1 (1) Level 2 (2) Level 3 (3) Total December 31, 2017 Assets: Derivative contracts $ 3,091 $ 1,267 $ — $ 4,358 Liabilities: Derivative contracts $ 693 $ 535 $ — $ 1,228 December 31, 2016 Assets: Derivative contracts $ 256 $ 2,395 $ — $ 2,651 Liabilities: Derivative contracts $ 60 $ 1,667 $ — $ 1,727 (1) quoted prices in active markets for identical assets or liabilities (2) observable inputs other than quoted prices in active markets for identical assets and liabilities (3) no observable pricing inputs in the market

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative Instruments [Abstract]
Summarized volume of GRE's outstanding contracts and options	Commodity Settlement Dates Volume Electricity First quarter 2018 739,120 MWh Electricity Third quarter 2018 339,440 MWh Electricity Fourth quarter 2018 209,920 MWh Natural gas First quarter 2018 2,873,215 Dth Natural gas Second quarter 2018 306,725 Dth Natural gas Third quarter 2018 57,125 Dth Natural gas Fourth quarter 2018 66,030 Dth Natural gas First quarter 2019 61,350 Dth Natural gas Second quarter 2019 35,100 Dth Natural gas Third quarter 2019 19,050 Dth
Schedule of fair value of outstanding derivative instruments recorded as assets and liability	December 31 (in thousands) 2017 2016 Asset Derivatives Balance Sheet Location Derivatives not designated or not qualifying as hedging instruments: Energy contracts and options Other current assets $ 4,358 $ 2,651 Liability Derivatives Derivatives not designated or not qualifying as hedging instruments: Energy contracts and options Other current liabilities $ 1,228 $ 1,727
Effects of derivative instruments on the consolidated statements of operations	Amount of Gain (Loss) Year ended December 31, (in thousands) 2017 2016 2015 Derivatives not designated or not qualifying as hedging instruments Location of Loss Recognized on Derivatives Energy contracts and options Cost of revenues $ (1,291 ) $ (538 ) $ (1,772 )

Investment in Joint Ventures (T

Investment in Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2017
Shoreditch [Member]
Schedule of Equity Method Investments [Line Items]
Summary of change in balance of company's investment	Balance, beginning of period $ — Capital contributions 3,970 Cumulative foreign currency translation adjustment 45 Equity in the net loss of joint venture (565 ) Balance, end of period $ 3,450
Summary of unaudited statements of operations	REVENUES $ — OPERATING EXPENSES: Cost of revenues 8 Selling, general and administrative 779 TOTAL OPERATING EXPENSES 787 Loss from operations (787 ) Other — NET LOSS $ (787 )
Summary of unaudited balance sheet	Assets Cash and cash equivalents $ 2,787 Other current assets 79 Other assets 189 Total assets $ 3,055 Liabilities and member’s interest Current liabilities $ 18 Member’s interest 3,037 Total liabilities and member’s interest $ 3,055
AMSO, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Summary of change in balance of company's investment	Year ended December 31, (in thousands) 2017 2016 2015 Balance, beginning of period $ — $ (399 ) $ (252 ) Capital contributions — 63 250 Equity in net loss of AMSO, LLC — (222 ) (397 ) Elimination of the investment in AMSO, LLC — 558 — Balance, end of period $ — $ — $ (399 )
Summary of unaudited statements of operations	(in thousands) Period from January 1, 2016 to April 30, 2016 Year ended December 31, 2015 REVENUES $ — $ — OPERATING EXPENSES: General and administrative 120 403 Research and development 3,512 4,782 TOTAL OPERATING EXPENSES 3,632 5,185 Loss from operations (3,632 ) (5,185 ) Other income — — NET LOSS $ (3,632 ) $ (5,185 )
Summary of unaudited balance sheet	Assets Cash and cash equivalents $ 750 Receivable from Total 3,000 Other current assets 128 Other assets 860 Total assets $ 4,738 Liabilities and member’s interest Current liabilities $ 518 Asset retirement obligations 2,535 Other liabilities 981 Member’s interest 704 Total liabilities and member’s interest $ 4,738
Summary of revenue, net (loss) income from operations of AMSO, LLC	(in thousands) Year ended December 31, 2016 Revenues $ — Income from operations $ 118 Net income $ 76 Year ended December 31, (in thousands) 2016 2015 Revenues $ 212,112 $ 213,056 Net loss $ (35,602 ) $ (13,424 )
Summary change in the balance of the AMSO, LLC retirement obligations	(in thousands) Year ended December 31, Period from April 30, Balance, beginning of period $ 116 $ 2,535 Adjustments (60 ) (441 ) Payments (56 ) (1,978 ) Balance, end of period $ — $ 116

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Property and Equipment [Abstract]
Schedule of property and equipment	December 31 (in thousands) 2017 2016 Computer software and development $ 1,912 $ 1,836 Computers and computer hardware 246 231 Laboratory and drilling equipment 3,833 543 Office equipment and other 443 424 6,434 3,034 Less: accumulated depreciation (2,414 ) (1,417 ) Property and equipment, net $ 4,020 $ 1,617

Goodwill and Other Intangibles

Goodwill and Other Intangibles (Tables)	12 Months Ended
	Dec. 31, 2017
Goodwill and Other Intangibles [Abstract]
Schedule of goodwill	(in thousands) Balance at December 31, 2014 $ 3,663 Change in carrying amount — Balance at December 31, 2015 3,663 Acquisition of Retail Energy Holdings, LLC (see Note 2) 5,065 Balance at December 31, 2016 8,728 Acquisition of Mirabito Natural Gas (see Note 2) 1,270 Balance at December 31, 2017 $ 9,998
Schedule of other intangible assets	(in thousands) Weighted Average Amortization Period Gross Carrying Amount Accumulated Amortization Net December 31, 2017 Patents and trademarks 20 years $ 2,860 $ (135 ) $ 2,725 Non-compete agreement 2 years 115 (65 ) 50 Customer relationships 4.4 years 3,200 (1,266 ) 1,934 Licenses — 150 — 150 TOTAL 11.3 years $ 6,325 $ (1,466 ) $ 4,859 December 31, 2016 Trademark 20 years $ 2,100 $ (13 ) $ 2,087 Non-compete agreement 2 years 110 (11 ) 99 Customer relationships 2 years 2,100 (159 ) 1,941 Licenses — 150 — 150 TOTAL 10.4 years $ 4,460 $ (183 ) $ 4,277

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Schedule of components of income (loss) before income taxes	Year ended December 31, (in thousands) 2017 2016 2015 Domestic $ 7,122 $ 18,629 $ 1,517 Foreign (14,044 ) (48,603 ) (9,628 ) LOSS BEFORE INCOME TAXES $ (6,922 ) $ (29,974 ) $ (8,111 )
Schedule of components of deferred income tax assets	December 31 (in thousands) 2017 2016 Deferred income tax assets: Bad debt reserve $ 302 $ 70 Accrued expenses 4,425 3,821 State taxes 117 221 Charitable contributions 265 470 Net operating loss 37,435 37,568 Stock options and restricted stock 908 1,456 Depreciation 7,026 11,153 Total deferred income tax assets 50,478 54,759 Valuation allowance (48,337 ) (52,978 ) DEFERRED INCOME TAX ASSETS, NET $ 2,141 $ 1,781
Schedule of components of income taxes provision	Year ended December 31, (in thousands) 2017 2016 2015 Current: Federal $ — $ — $ — State and local (1,366 ) (2,349 ) (704 ) Foreign — (8 ) — (1,366 ) (2,357 ) (704 ) Deferred: Federal — (6 ) (19 ) State and local (360 ) 145 198 Foreign — — — (360 ) 139 179 PROVISION FOR INCOME TAXES $ (1,726 ) $ (2,218 ) $ (525 )
Schedule of income tax reconciliation	Year ended December 31, (in thousands) 2017 2016 2015 U.S. federal income tax benefit at statutory rate $ 2,423 $ 10,491 $ 2,840 Valuation allowance 11,694 (21,209 ) (10,687 ) Foreign tax rate differential (2,610 ) 9,901 7,674 Tax law change (11,070 ) — — Deferred income tax adjustment (1,250 ) — — Other 66 95 (20 ) State and local income tax, net of federal benefit (979 ) (1,496 ) (332 ) PROVISION FOR INCOME TAXES $ (1,726 ) $ (2,218 ) $ (525 )
Schedule of change in the valuation allowance for deferred income taxes	(in thousands) Balance at beginning of period Additions charged to costs and expenses Deductions Balance at end of Year ended December 31, 2017 Reserves for valuation allowances deducted from deferred income taxes, net $ 52,978 $ 7,053 $ (11,694 ) $ 48,337 Year ended December 31, 2016 Reserves for valuation allowances deducted from deferred income taxes, net $ 31,769 $ 21,209 $ — $ 52,978 Year ended December 31, 2015 Reserves for valuation allowances deducted from deferred income taxes, net $ 21,082 $ 10,687 $ — $ 31,769
Schedule of change in the balance of unrecognized income tax benefits	Year ended December 31, (in thousands) 2017 2016 2015 Balance at beginning of period $ 632 $ 636 $ 543 Additions based on tax positions related to the current period 100 81 97 Additions for tax positions of prior periods 1 4 10 Lapses of statutes of limitations (175 ) (89 ) (14 ) Balance at end of period $ 558 $ 632 $ 636

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Stock-Based Compensation [Abstract]
Summary of status of company's grants of restricted shares of Class B common stock	Number of Weighted- Average Grant Date Fair Non-vested shares at December 31, 2016 26 $ 10.08 Granted 182 5.77 Vested (45 ) 8.36 Forfeited — — NON-VESTED SHARES AT DECEMBER 31, 2017 163 $ 6.19
Equity compensation plans, valuation assumptions	Year ended December 31, 2016 2015 ASSUMPTIONS Average risk-free interest rate 0.4 % 0.93 % Expected dividend yield 5.01 % — Expected volatility 55.5 % 61.0 % Expected term 1 year 5.5 years Weighted-average grant date fair value of options granted $ 1.05 $ 9.67
Summary of stock option activity	Number of Options Weighted- Average Exercise Weighted- Average Remaining Contractual Term Aggregate Intrinsic Value Outstanding at December 31, 2016 414 $ 6.75 4.6 $ 37 Granted — — Exercised (16 ) 6.85 Cancelled/Forfeited (15 ) 4.05 OUTSTANDING AT DECEMBER 31, 2017 383 $ 6.85 3.8 $ — EXERCISABLE AT DECEMBER 31, 2017 327 $ 6.85 3.8 $ —

Variable Interest Entity (Table

Variable Interest Entity (Tables)	12 Months Ended
	Dec. 31, 2017
Variable Interest Entity [Abstract]
Schedule of net (loss) income related to CCE and aggregate net funding	Year ended December 31, (in thousands) 2017 2016 2015 Net income (loss) $ 112 $ (1,136 ) $ 34 Aggregate funding repaid to (provided by) the Company, net 158 (871 ) 950
Summarized consolidated balance sheet amounts related to CCE	December 31 (in thousands) 2017 2016 ASSETS Cash and cash equivalents $ 52 $ 150 Restricted cash 31 17 Trade accounts receivable 1,031 1,008 Prepaid expenses 451 450 Other current assets 31 26 Other assets 439 439 TOTAL ASSETS $ 2,035 $ 2,090 LIABILITIES AND NONCONTROLLING INTERESTS Current liabilities $ 698 $ 707 Due to IDT Energy 1,140 1,298 Noncontrolling interests 197 85 TOTAL LIABILITIES AND NONCONTROLLING INTERESTS $ 2,035 $ 2,090

Accumulated Other Comprehensi40

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2017
Equity & Accumulated Other Comprehensive Income [Abstract]
Summary of accumulated balances for other comprehensive income	(in thousands) Foreign currency translation Balance at December 31, 2014 $ 10 Other comprehensive income attributable to Genie 144 Balance at December 31, 2015 154 Other comprehensive income attributable to Genie 1,311 Balance at December 31, 2016 1,465 Other comprehensive income attributable to Genie 1,580 BALANCE AT DECEMBER 31, 2017 $ 3,045

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies [Abstract]
Schedule of future minimum payments for operating leases	(in thousands) Year ending December 31: 2018 $ 193 2019 77 2020 41 2021 — 2022 — Thereafter — Total payments $ 311

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Summary of related party transactions	Year ended December 31, (in thousands) 2017 2016 2015 Amount IDT charged the Company $ 1,773 $ 2,197 $ 2,340 Amount the Company charged IDT 471 627 546

Business Segment and Geograph43

Business Segment and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2017
Business Segment and Geographic Information [Abstract]
Summary of operating results for the business segments	(in thousands) GRE Afek GOGAS Corporate Total Year ended December 31, 2017 Revenues $ 264,202 $ — $ — $ — $ 264,202 Income (loss) from operations 16,586 (12,698 ) (593 ) (9,835 ) (6,540 ) Depreciation and amortization 1,740 327 72 1 2,140 Exploration — 4,879 — — 4,879 Write-off of capitalized exploration costs — 6,483 — — 6,483 Equity in the net loss of Shoreditch 565 — — — 565 Year ended December 31, 2016 Revenues $ 212,112 $ — $ — $ — $ 212,112 Income (loss) from operations 26,503 (48,272 ) 439 (9,183 ) (30,513 ) Depreciation and amortization 427 124 29 1 581 Research and development — — (269 ) — (269 ) Exploration — 6,088 — — 6,088 Write-off of capitalized exploration costs — 41,041 — — 41,041 Equity in the net loss of AMSO, LLC — — 222 — 222 Year ended December 31, 2015 Revenues $ 213,056 $ — $ — $ — $ 213,056 Income (loss) from operations 11,095 (7,458 ) (3,058 ) (8,908 ) (8,329 ) Depreciation 245 104 78 1 428 Research and development — 63 1,922 — 1,985 Exploration — 6,583 — — 6,583 Equity in the net loss of AMSO, LLC — — 397 — 397
Summary of total assets for the business segments	(in thousands) GRE Afek GOGAS Corporate Total Total assets: December 31, 2017 $ 112,521 $ 2,588 $ 7,887 $ 2,782 $ 125,778 December 31, 2016 87,539 6,685 12,224 15,365 121,813 December 31, 2015 80,177 38,665 17,770 19,203 155,815
Schedule of net long-lived assets and total assets held outside of the United States	(in thousands) United Foreign Countries Total December 31, 2017 Long-lived assets, net $ 696 $ 3,352 $ 4,048 Total assets 115,605 10,173 125,778 December 31, 2016 Long-lived assets, net $ 1,060 $ 582 $ 1,642 Total assets 113,158 8,655 121,813 December 31, 2015 Long-lived assets, net $ 763 $ 646 $ 1,409 Total assets 114,880 40,935 155,815

Selected Quarterly Financial 44

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Selected Quarterly Financial Data (Unaudited) [Abstract]
Schedule of selected quarterly financial data of the company	Quarter Ended Income (loss) Net income (loss) attributable (Loss) earnings per (in thousands, except per share data) Revenues Cost of revenues from operations Net (loss) income to Genie Energy Ltd. Basic Diluted 2017: December 31 (1) $ 73,077 $ 46,321 $ 430 $ (812 ) $ 215 $ (0.01 ) $ (0.01 ) September 30 (2) 69,473 47,694 1,403 975 778 0.02 0.02 June 30 (3) 50,247 38,122 (13,569 ) (12,950 ) (12,569 ) (0.55 ) (0.55 ) March 31 71,405 46,556 5,196 4,139 4,582 0.18 0.18 TOTAL $ 264,202 $ 178,693 $ (6,540 ) $ (8,648 ) $ (6,994 ) $ (0.36 ) $ (0.36 ) 2016: December 31 $ 51,519 $ 36,949 $ (1,344 ) $ (1,285 ) $ (816 ) $ (0.05 ) $ (0.05 ) September 30 (1) 57,153 36,946 (37,102 ) (37,174 ) (32,139 ) (1.43 ) (1.43 ) June 30 44,561 26,445 1,934 1,417 2,761 0.10 0.10 March 31 58,879 34,832 5,999 4,850 5,669 0.23 0.22 TOTAL $ 212,112 $ 135,172 $ (30,513 ) $ (32,192 ) $ (24,525 ) $ (1.14 ) $ (1.14 ) (1) In the fourth quarter of 2017 and in the third quarter of 2016, loss from operations included write-off of capitalized exploration costs of $6.5 million and $41.0 million, respectively. (2) In the third quarter of 2017, the Company recognized a liability of $1.5 million for a tentative agreement in principle with the New Jersey Office of the Attorney General regarding concerns related to energy supply charges issued to our retail customers during the first quarter of 2014. The Company recorded the liability as a revenue reduction of $1.3 million and an expense of $0.2 million. (3) In the second quarter of 2017, the Company recognized a liability of $9.0 million for the preliminary settlement of certain class action lawsuits. The Company recorded the liability as a revenue reduction of $3.6 million and an expense of $5.4 million.

Description of Business and S45

Description of Business and Summary of Significant Accounting Policies (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the calculation of diluted earnings per share	1,145	1,640	2,266
Stock options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the calculation of diluted earnings per share	383	414	414
Non-vested restricted Class B common stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from the calculation of diluted earnings per share	762	1,226	1,852

Description of Business and S46

Description of Business and Summary of Significant Accounting Policies (Details 1)	12 Months Ended
	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Con Edison [Member] | Consolidated revenues [Member]
Concentration Risk [Line Items]
Concentration risk percentage	15.00%		20.00%		23.00%
Con Edison [Member] | Consolidated gross trade accounts receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage	11.00%		15.00%
ComEd [Member] | Consolidated revenues [Member]
Concentration Risk [Line Items]
Concentration risk percentage	10.00%		13.00%			[1]
ComEd [Member] | Consolidated gross trade accounts receivable [Member]
Concentration Risk [Line Items]
Concentration risk percentage		[2]	10.00%
National Grid USA [Member] | Consolidated revenues [Member]
Concentration Risk [Line Items]
Concentration risk percentage		[1]		[1]	12.00%
[1]	less than 10% of consolidated revenue in the period
[2]	less than 10% of consolidated gross trade accounts receivable

Description of Business and S47

Description of Business and Summary of Significant Accounting Policies (Details 2) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at beginning of period		$ 171	$ 182	$ 227
Additions charged (reversals credited) to expense		762	8	(29)
Additions (deductions)	[1]	(166)	19	16
Balance at end of period		$ 1,099	$ 171	$ 182
[1]	Primarily uncollectible accounts written off, net of recoveries.

Description of Business and S48

Description of Business and Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Description of Business and Summary of Significant Accounting Policies (Textual)
Underground storage facilities		$ 1	$ 0.6
Inventory renewable energy credits		3	5.4
Amount of advertising expense included in selling general and administrative expense		$ 2.1	$ 1.4	$ 0.9
Description of percentage of consolidated revenue from utility companies		The percentage of consolidated revenues from customers by utility company that equal or exceed 10% of consolidated revenues in the period (no other single utility company accounted for more than 10% of consolidated revenues in these periods.
Description of percentage of consolidated gross trade accounts receivable by utility companies		The percentage of consolidated gross trade accounts receivable by utility company that equal or exceed 10% of consolidated gross trade accounts receivable at December 31, 2017 and 2016.
Purchase method, description		The fair value of patents and trademarks, non-compete agreements and customer relationships acquired in a business combination accounted for under the purchase method are amortized over their estimated useful lives as follows: patents and trademarks are amortized on a straight-line basis over the 20-year period of expected cash flows; non-compete agreements are amortized on a straight-line basis over their 2 year term; and customer relationships are amortized ratably over the 2 or 9 year period of expected cash flows.
Customer Relationships [Member] | Maximum [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Amortization period		9 years
Customer Relationships [Member] | Minimum [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Amortization period		2 years
Patents and trademarks [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Amortization period		20 years
Non-compete agreement [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Amortization period		2 years
Computer software and development [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Estimated useful lives		2, 3 or 5 years
Computers and computer hardware [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Estimated useful lives		5 years
Laboratory and drilling equipment [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Estimated useful lives		7 years
Office equipment and other [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Estimated useful lives		5 or 7 years
Genie Retail Energy [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Company's investment, ownership percentage in subsidiary		100.00%
Ownership interest of company		1.25%
Genie Oil and Gas, Inc. [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Company's investment, ownership percentage in subsidiary		92.00%
Afek Oil and Gas, Ltd. [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Company's investment, ownership percentage in subsidiary		86.10%
Genie Energy International Corporation [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Company's investment, ownership percentage in subsidiary		99.30%
GOGAS [Member] | Subsequent Event [Member]
Description of Business and Summary of Significant Accounting Policies (Textual)
Company's investment, ownership percentage in subsidiary	5.00%
Fair value of common stock	$ 0.2

Acquisitions (Details)

Acquisitions (Details) - USD ($) $ in Thousands	Aug. 10, 2017	Nov. 02, 2016
Supplemental information:
Cash paid		$ 10,900
Mirabito Natural Gas [Member]
Business Acquisition [Line Items]
Trade accounts receivable	$ 509
Prepaid expenses	60
Non-compete agreement	5
Customer relationships	1,100
Patents and trademarks	760
Goodwill	1,270
Other assets	465
Trade accounts payable	(299)
Accrued expenses	(2)
Net assets excluding cash acquired	3,868
Supplemental information:
Cash paid	3,955
Cash acquired	(87)
Total consideration, net of cash acquired	$ 3,868
Retail Energy Holdings, LLC [Member]
Business Acquisition [Line Items]
Trade accounts receivable		3,614
Inventory		287
Prepaid expenses		81
Other current assets		26
Property and equipment		110
Trademark		2,100
Non-compete agreement		110
Customer relationships		2,100
Goodwill		5,065
Other assets		1,600
Revolving line of credit		(1,919)
Trade accounts payable		(2,620)
Accrued expenses		(1,542)
Net assets excluding cash acquired		9,012
Supplemental information:
Cash paid		10,949
Cash acquired		(2,249)
Cash paid, net of cash acquired		8,700
Liability for additional purchase price (paid in 2017)		312
Total consideration, net of cash acquired		$ 9,012

Acquisitions (Details 1)

Acquisitions (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquisition of Retail Energy Holdings, LLC [Member]
Business Acquisition [Line Items]
Revenue		$ 243,147	$ 243,165
Net loss		(32,303)	$ (11,256)
Acquisition Of Mirabito Natural Gas [Member]
Business Acquisition [Line Items]
Revenue	$ 268,008	217,448
Net loss	$ (8,588)	$ (32,031)

Acquisitions (Details Textual)

Acquisitions (Details Textual) - USD ($) $ in Thousands	Aug. 10, 2017	Nov. 02, 2016
Acquisitions (Textual)
Privately held owner		$ 9,500
Working capital		1,400
Aggregate cash payment		$ 10,900
Management Agreement [Member]
Acquisitions (Textual)
Management fee termination date	Aug. 31, 2021
Annual management fee business profit percentage	30.00%
Annual management fee minimum	$ 250,000
Retail Energy Holdings, LLC [Member] | Customer Relationships [Member]
Acquisitions (Textual)
Amortization period		2 years
Mirabito Natural Gas [Member]
Acquisitions (Textual)
Aggregate cash payment	$ 4,000
Mirabito Natural Gas [Member] | Customer Relationships [Member]
Acquisitions (Textual)
Amortization period	9 years

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Recurring [Member] - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Assets:
Derivative contracts		$ 4,358	$ 2,651
Liabilities:
Derivative contracts		1,228	1,727
Level 1 [Member]
Assets:
Derivative contracts	[1]	3,091	256
Liabilities:
Derivative contracts	[1]	693	60
Level 2 [Member]
Assets:
Derivative contracts	[2]	1,267	2,395
Liabilities:
Derivative contracts	[2]	535	1,667
Level 3 [Member]
Assets:
Derivative contracts	[3]
Liabilities:
Derivative contracts	[3]
[1]	Quoted prices in active markets for identical assets or liabilities.
[2]	Observable inputs other than quoted prices in active markets for identical assets and liabilities.
[3]	No observable pricing inputs in the market.

Fair Value Measurements (Deta53

Fair Value Measurements (Details Textual) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value Measurements (Textual)
Financial instrument included in other assets	$ 0.6	$ 1

Derivative Instruments (Details

Derivative Instruments (Details)	12 Months Ended
	Dec. 31, 2017
Electricity [Member]
Summarized volume of GRE's outstanding
Commodity	Electricity
Settlement Dates	Mar. 31, 2018
Volume	739,120 MWh
Electricity 1 [Member]
Summarized volume of GRE's outstanding
Commodity	Electricity
Settlement Dates	Sep. 30, 2018
Volume	339,440 MWh
Electricity 2 [Member]
Summarized volume of GRE's outstanding
Commodity	Electricity
Settlement Dates	Dec. 31, 2018
Volume	209,920 MWh
Natural Gas [Member]
Summarized volume of GRE's outstanding
Commodity	Natural gas
Settlement Dates	Mar. 31, 2018
Volume	2,873,215 Dth
Natural Gas 1 [Member]
Summarized volume of GRE's outstanding
Commodity	Natural gas
Settlement Dates	Jun. 30, 2018
Volume	306,725 Dth
Natural Gas 2 [Member]
Summarized volume of GRE's outstanding
Commodity	Natural gas
Settlement Dates	Sep. 30, 2018
Volume	57,125 Dth
Natural Gas 3 [Member]
Summarized volume of GRE's outstanding
Commodity	Natural gas
Settlement Dates	Dec. 31, 2018
Volume	66,030 Dth
Natural Gas 4 [Member]
Summarized volume of GRE's outstanding
Commodity	Natural gas
Settlement Dates	Mar. 31, 2019
Volume	61,350 Dth
Natural Gas 5 [Member]
Summarized volume of GRE's outstanding
Commodity	Natural gas
Settlement Dates	Jun. 30, 2019
Volume	35,100 Dth
Natural Gas 6 [Member]
Summarized volume of GRE's outstanding
Commodity	Natural gas
Settlement Dates	Sep. 30, 2019
Volume	19,050 Dth

Derivative Instruments (Detai55

Derivative Instruments (Details 1) - Energy contracts and options [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other current assets [Member]
Schedule of fair value of outstanding derivative instruments recorded as assets and liability
Asset Derivatives, not designated or not qualifying as hedging instruments	$ 4,358	$ 2,651
Other Current Liabilities [Member]
Schedule of fair value of outstanding derivative instruments recorded as assets and liability
Liability Derivatives, not designated or not qualifying as hedging instruments	$ 1,228	$ 1,727

Derivative Instruments (Detai56

Derivative Instruments (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Energy contracts and options [Member] | Cost of revenues [Member]
Effects of derivative instruments on the consolidated statements of operations
Amount of Loss Recognized on Derivatives	$ (1,291)	$ (538)	$ (1,772)

Afek Oil and Gas Exploration 57

Afek Oil and Gas Exploration Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Afek Oil and Gas Exploration Activities (Textual)
Write-off of capitalized exploration costs	$ 6,483	$ 41,041

Investment in Joint Ventures (D

Investment in Joint Ventures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of change in balance of company's investment
Balance, beginning of period
Capital contributions	3,970
Equity in net loss of AMSO, LLC	(565)	(222)	(397)
Balance, end of period	3,450
AMSO, LLC [Member]
Summary of change in balance of company's investment
Balance, beginning of period		(399)	(252)
Capital contributions		63	250
Equity in net loss of AMSO, LLC		(222)	(397)
Elimination of the investment in AMSO, LLC		558
Balance, end of period			$ (399)

Investment in Joint Ventures 59

Investment in Joint Ventures (Details 1) - AMSO, LLC [Member] - USD ($) $ in Thousands	4 Months Ended	12 Months Ended
	Apr. 30, 2016	Dec. 31, 2015
Summary of unaudited statements of operations of AMSO, LLC
REVENUES
OPERATING EXPENSES:
General and administrative	120	403
Research and development	3,512	4,782
TOTAL OPERATING EXPENSES	3,632	5,185
Loss from operations	(3,632)	(5,185)
Other income
NET LOSS	$ (3,632)	$ (5,185)

Investment in Joint Ventures 60

Investment in Joint Ventures (Details 2) - USD ($) $ in Thousands	Dec. 31, 2017	Apr. 30, 2016
Shoreditch [Member]
Assets
Cash and cash equivalents	$ 2,787
Other current assets	79
Other assets	189
Total assets	3,055
Liabilities and member's interest
Current liabilities	18
Member's interest	3,037
Total liabilities and member's interest	$ 3,055
AMSO, LLC [Member]
Assets
Cash and cash equivalents		$ 750
Receivable from Total		3,000
Other current assets		128
Other assets		860
Total assets		4,738
Liabilities and member's interest
Current liabilities		518
Asset retirement obligations		2,535
Other liabilities		981
Member's interest		704
Total liabilities and member's interest		$ 4,738

Investment in Joint Ventures 61

Investment in Joint Ventures (Details 3) - AMSO, LLC [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Summary of revenue, net (loss) income from operations of AMSO, LLC
Revenues
Income from operations	118
Net income	76
Revenues	212,112	$ 213,056
Net loss	$ (35,602)	$ (13,424)

Investment in Joint Ventures 62

Investment in Joint Ventures (Details 4) - AMSO, LLC [Member] - USD ($) $ in Thousands	8 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017
Summary of retirement obligations after the consolidation of AMSO, LLC
Balance, beginning of period	$ 2,535	$ 116
Adjustments	(441)	(60)
Payments	(1,978)	(56)
Balance, end of period	$ 116

Investment in Joint Ventures 63

Investment in Joint Ventures (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Balance, beginning of period
Capital contributions	3,970
Equity in the net loss of joint venture	(565)	(222)	$ (397)
Balance, end of period	3,450
Shoreditch [Member]
Schedule of Equity Method Investments [Line Items]
Balance, beginning of period
Capital contributions	3,970
Cumulative foreign currency translation adjustment	45
Equity in the net loss of joint venture	(565)
Balance, end of period	$ 3,450

Investment in Joint Ventures 64

Investment in Joint Ventures (Details 6) - Shoreditch [Member] $ in Thousands	5 Months Ended
	Dec. 31, 2017USD ($)
Schedule of Equity Method Investments [Line Items]
REVENUES
OPERATING EXPENSES:
Cost of revenues	8
Selling, general and administrative	779
Operating Expenses	787
Loss from operations	(787)
Other
NET LOSS	$ (787)

Investment in Joint Ventures 65

Investment in Joint Ventures (Details Textual) $ in Thousands, £ in Millions	4 Months Ended	12 Months Ended
	Apr. 30, 2016USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2017GBP (£)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Apr. 02, 2016USD ($)	Dec. 31, 2014USD ($)
Business Acquisition [Line Items]
Gain on consolidation of AMSO, LLC	$ 1,300			$ 1,262
Decommissioning liability settlement amount not refundable						$ 3,000
Investment in joint venture		3,970
Allocated to goodwill		9,998		8,728	$ 3,663		$ 3,663
Goodwill		$ 1,270		$ 5,065
GOGAS [Member]
Business Acquisition [Line Items]
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions		98.30%	98.30%
Shoreditch [Member]
Business Acquisition [Line Items]
Investment in joint venture		$ 3,970
Loss on investment		3,500
GEUK [Member]
Business Acquisition [Line Items]
Investment in joint venture		$ 4,000
Percentage of ownership		65.00%
Goodwill		$ 500
Additional aggregate investment in joint venture		$ 3,000	£ 2.2
EGC [Member]
Business Acquisition [Line Items]
Percentage of ownership		35.00%
Additional aggregate investment in joint venture		$ 2,200	£ 1.7

Property and Equipment (Details

Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 6,434	$ 3,034
Less: accumulated depreciation	(2,414)	(1,417)
Property and equipment, net	4,020	1,617
Computer software and development [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,912	1,836
Computers and computer hardware [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	246	231
Laboratory and drilling equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	3,833	543
Office equipment and other [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 443	$ 424

Property and Equipment (Detai67

Property and Equipment (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property and equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 0.8	$ 0.4	$ 0.4

Goodwill and Other Intangible68

Goodwill and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Other Intangibles [Abstract]
Beginning Balance	$ 8,728	$ 3,663	$ 3,663
Change in carrying amount
Acquisition of Retail Energy Holdings, LLC and Mirabito Natural Gas (see Note 2)	1,270	5,065
Ending Balance	$ 9,998	$ 8,728	$ 3,663

Goodwill and Other Intangible69

Goodwill and Other Intangibles (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	11 years 3 months 19 days	10 years 4 months 24 days
Gross Carrying Amount	$ 6,325	$ 4,460
Accumulated Amortization	(1,466)	(183)
Net Balance	$ 4,859	$ 4,277
Patents and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	20 years	20 years
Gross Carrying Amount	$ 2,860	$ 2,100
Accumulated Amortization	(135)	(13)
Net Balance	$ 2,725	$ 2,087
Non-compete agreement [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	2 years	2 years
Gross Carrying Amount	$ 115	$ 110
Accumulated Amortization	(65)	(11)
Net Balance	$ 50	$ 99
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	4 years 4 months 24 days	2 years
Gross Carrying Amount	$ 3,200	$ 2,100
Accumulated Amortization	(1,266)	(159)
Net Balance	$ 1,934	$ 1,941
Licenses [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Amortization Period	0 years	0 years
Gross Carrying Amount	$ 150	$ 150
Accumulated Amortization
Net Balance	$ 150	$ 150

Goodwill and Other Intangible70

Goodwill and Other Intangibles (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Other Intangibles (Textual)
Amortization expense of intangible assets	$ 1.3	$ 0.2
Amortization expense of finite lives intangible assets, 2018	1.2
Amortization expense of finite lives intangible assets, 2019	0.3
Amortization expense of finite lives intangible assets, 2020	0.3
Amortization expense of finite lives intangible assets, 2021	0.3
Amortization expense of finite lives intangible assets, 2022	$ 0.3

Revolving Lines of Credit (Deta

Revolving Lines of Credit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 31, 2017	Apr. 04, 2017	Dec. 17, 2015
Revolving Lines of Credit (Textual)
Revolving loan facility	$ 2,513
Settlement of obligations	12,655	6,690
Gain from revolving loan facility		200
Revolving line of credit		711
JPMorgan [Member]
Revolving Lines of Credit (Textual)
Maximum principal amount on revolving line of credit		25,000
Description of line of credit collateral	Equal to the greater of (a) $10.0 million or (b) the sum of the amount of letters of credit outstanding plus the outstanding principal under the revolving note.
Maximum amount of collateral under condition one	$ 10,000
Interest rate on principal outstanding, description	Lesser of (a) the LIBOR rate multiplied by the statutory reserve rate established by the Board of Governors of the Federal Reserve System plus 1.0% per annum, or (b) the maximum rate per annum permitted by whichever of applicable federal or Texas laws permit the higher interest rate.
Quoted margin rate on LIBOR, per annum	1.00%
Maturity date	May 31, 2017
Line of credit facility, frequency of payment and payment terms	Interest was payable at least every three months
Cash collateral for line of credit		10,000
Cash collateral released				$ 10,000
Line of credit facility, amount outstanding		8,100
Vantage Commodities Financial Services II, LLC [Member] | REH [Member]
Revolving Lines of Credit (Textual)
Revolving loan facility		700
Maximum principal amount on revolving line of credit	$ 7,500
Interest rate on principal outstanding, description	The principal outstanding incurred interest at one-month LIBOR plus 5.25% per annum, payable monthly.
Maturity date	Oct. 31, 2017
Vantage Commodities Financial Services II, LLC [Member] | GRE Credit Agreement [Member]
Revolving Lines of Credit (Textual)
Revolving loan facility					$ 2,500
Initial amount borrowed lines of credit current					4,300
Maximum principal amount on revolving line of credit					20,000
Interest rate on principal outstanding, description	Outstanding principal amount incurs interest at LIBOR plus 4.5% per annum.
Effective interest rate	5.99%
Maturity date	Apr. 3, 2020
Amount outstanding added to lines of credit current					$ 1,700
Maple Bank GmbH [Member] | GRE [Member]
Revolving Lines of Credit (Textual)
Revolving loan facility						$ 2,000
Settlement of obligations		1,800
Gain from revolving loan facility		$ 200

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of components of (loss) income before income taxes
Domestic	$ 7,122	$ 18,629	$ 1,517
Foreign	(14,044)	(48,603)	(9,628)
LOSS BEFORE INCOME TAXES	$ (6,922)	$ (29,974)	$ (8,111)

Income Taxes (Details 1)

Income Taxes (Details 1) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred income tax assets:
Bad debt reserve	$ 302	$ 70
Accrued expenses	4,425	3,821
State taxes	117	221
Charitable contributions	265	470
Net operating loss	37,435	37,568
Stock options and restricted stock	908	1,456
Depreciation	7,026	11,153
Total deferred income tax assets	50,478	54,759
Valuation allowance	(48,337)	(52,978)	$ (31,769)	$ (21,082)
DEFERRED INCOME TAX ASSETS, NET	$ 2,141	$ 1,781

Income Taxes (Details 2)

Income Taxes (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal
State and local	(1,366)	(2,349)	(704)
Foreign		(8)
Total current income taxes	(1,366)	(2,357)	(704)
Deferred:
Federal		(6)	(19)
State and local	(360)	145	198
Foreign
Total deferred income taxes	(360)	139	179
PROVISION FOR INCOME TAXES	$ (1,726)	$ (2,218)	$ (525)

Income Taxes (Details 3)

Income Taxes (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Effective Income Tax Rate Reconciliation, Amount [Abstract]
U.S. federal income tax benefit at statutory rate	$ 2,423	$ 10,491	$ 2,840
Valuation allowance	11,694	(21,209)	(10,687)
Foreign tax rate differential	(2,610)	9,901	7,674
Tax law change	(11,070)
Deferred income tax adjustment	(1,250)
Other	66	95	(20)
State and local income tax, net of federal benefit	(979)	(1,496)	(332)
PROVISION FOR INCOME TAXES	$ (1,726)	$ (2,218)	$ (525)

Income Taxes (Details 4)

Income Taxes (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of change in the valuation allowance for deferred income taxes
Balance at beginning of period	$ 52,978	$ 31,769	$ 21,082
Additions charged to costs and expenses	7,053	21,209	10,687
Deductions	(11,694)
Balance at end of period	$ 48,337	$ 52,978	$ 31,769

Income Taxes (Details 5)

Income Taxes (Details 5) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of change in the balance of unrecognized income tax benefits
Balance at beginning of period	$ 632	$ 636	$ 543
Additions based on tax positions related to the current period	100	81	97
Additions for tax positions of prior periods	1	4	10
Lapses of statutes of limitations	(175)	(89)	(14)
Balance at end of period	$ 558	$ 632	$ 636

Income Taxes (Details Textual)

Income Taxes (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 22, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes (Textual)
Accrued interest on income taxes		$ 1,000	$ 4,000	$ 4,000
Accrued interest included in current income taxes payable.		35,000	$ 34,000
Minimum [Member]
Income Taxes (Textual)
U.S. tax code, including a reduction in corporate tax rate	21.00%
Maximum [Member]
Income Taxes (Textual)
U.S. tax code, including a reduction in corporate tax rate	35.00%
Unconsolidated Entities [Member]
Income Taxes (Textual)
Net operating loss carryforwards		$ 1,000,000
Operating loss carryforwards, expiration date		Dec. 31, 2036
U.S. federal [Member]
Income Taxes (Textual)
Net operating loss carryforwards		$ 30,500,000
U.S. federal [Member] | Minimum [Member]
Income Taxes (Textual)
Operating loss carryforwards, expiration date		Dec. 31, 2033
Income tax returns period		2,014
U.S. federal [Member] | Maximum [Member]
Income Taxes (Textual)
Operating loss carryforwards, expiration date		Dec. 31, 2037
Income tax returns period		2,017
Foreign [Member]
Income Taxes (Textual)
Net operating loss carryforwards		$ 98,400,000
Operating loss carry forwards amount no expiration		$ 89,800,000
Foreign [Member] | Minimum [Member]
Income Taxes (Textual)
Income tax returns period		2,013
Foreign [Member] | Maximum [Member]
Income Taxes (Textual)
Income tax returns period		2,017
State [Member]
Income Taxes (Textual)
Net operating loss carryforwards		$ 113,400,000
State [Member] | Minimum [Member]
Income Taxes (Textual)
Operating loss carryforwards, expiration date		Dec. 31, 2029
Income tax returns period		2,013
State [Member] | Maximum [Member]
Income Taxes (Textual)
Operating loss carryforwards, expiration date		Dec. 31, 2038
Income tax returns period		2,017

Equity (Details)

Equity (Details) - USD ($)

May 09, 2015

Mar. 31, 2018

Feb. 15, 2018

Nov. 30, 2015

Nov. 15, 2015

Jul. 30, 2014

Jun. 30, 2011

Nov. 30, 2010

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Mar. 11, 2013

Equity (Textual)

Common stock dividend

$ 7,427,000

$ 5,914,000

$ 2,950,000

Remaining number of shares available for repurchase

6,900,000

Preferred stock dividend declared

$ 1,481,000

1,481,000

1,481,000

Proceeds from exercise of stock options

2,500,000

Employment agreement description

Dr. Harold Vinegar, Chief Scientist of the Company, has an option to purchase, at fair value, up to 10% of the GOGAS ventures in which he is a key contributor. In prior years, Dr. Vinegar purchased interests in IEI, Afek and Genie Mongolia.

Collection of receivables for issuance of equity

1,912,000

Sales of equity of subsidiaries

1,000,000

$ 2,500,000

Purchases of equity of subsidiary

(312,000)

Receivables for issuance of equity

Gogas [Member] | Michael Steinhardt [Member]

Equity (Textual)

Ownership acquire interest of company

1.50%

Total value of exercise of stock options

$ 5,000,000

Options expiration date

Apr. 9, 2015

Collection of receivables for issuance of equity

$ 800,000

Exercise price description

The exercise price of $5.0 million was paid $2.5 million in cash and $2.5 million in promissory notes that were due in November 2015. The notes incurred interest at 0.43% per annum, and were secured by 50% of the shares received in the exercise.

Receivables for issuance of equity

$ 1,700,000

Rupert Murdoch [Member] | Gogas [Member]

Equity (Textual)

Promissory note maturity date

Nov. 15, 2015

Sale of stock consideration by promissory note

$ 1,000,000

Sale of subsidiary stock percentage of ownership sold

0.50%

Collection of receivables for issuance of equity

$ 1,100,000

Note accrued interest

1.58%

Afek Oil and Gas, Ltd. [Member]

Equity (Textual)

Purchases of equity of subsidiary

$ 300,000

Purchases of equity of subsidiary interest

1.15%

Afek Oil and Gas, Ltd. [Member] | Harold Vinegar Chief Scientist [Member]

Equity (Textual)

Sales of equity of subsidiaries

$ 1,000,000

Sales of equity of subsidiaries interest

1.00%

Israel Energy Initiatives Ltd [Member] | Board of Directors Chairman [Member]

Equity (Textual)

Promissory notes

$ 2,500,000

Promissory note maturity date

Nov. 30, 2015

Promissory notes interest rate

0.43%

Promissory notes collateral

Secured by 50% of the shares received in the exercise.

Ownership acquire interest of company

1.50%

Total value of exercise of stock options

$ 5,000,000

American Shale Oil Limited Liability Company [Member] | Board of Directors Chairman [Member]

Equity (Textual)

Ownership acquire interest of company

1.70%

Genie Mongolia [Member] | Board of Directors Chairman [Member]

Equity (Textual)

Ownership acquire interest of company

1.50%

Preferred Stock [Member]

Equity (Textual)

Preferred stock dividend rate

$ 0.6376

$ 0.6376

$ 0.6376

Preferred Stock [Member] | Subsequent Event [Member]

Equity (Textual)

Preferred stock dividend rate

$ 0.1594

Record date of declared dividend

Feb. 6, 2018

Class A common stock

Equity (Textual)

Cash dividend paid

$ 0.30

$ 0.24

$ 0.12

Class A common stock | Subsequent Event [Member]

Equity (Textual)

Common stock dividends declared

$ 0.075

Paid date of declared dividend

Mar. 23, 2018

Record date of declared dividend

Mar. 19, 2018

Class B common stock

Equity (Textual)

Number of shares repurchased, shares

129,898

3,096

4,220

Number of shares repurchased, value

$ 800,000

$ 29,000

$ 27,000

Number of stock authorized to be repurchased

7,000,000

Cash dividend paid

$ 0.30

$ 0.24

$ 0.12

Commitment to purchase shares

600,000

Commitment to purchase shares price per share

$ 6.82

Class B common stock | Howards Jonas [Member]

Equity (Textual)

Commitment to purchase shares

3,600,000

Commitment to purchase shares price per share

$ 6.82

Class B common stock | Subsequent Event [Member]

Equity (Textual)

Common stock dividends declared

$ 0.075

Paid date of declared dividend

Mar. 23, 2018

Record date of declared dividend

Mar. 19, 2018

Sale of shares

1,152,074

Sale of shares price per share

$ 4.34

Amount of aggregate sales price

$ 5,000,000

Class B common stock | Subsequent Event [Member] | Howards Jonas [Member]

Equity (Textual)

Warrants to purchase shares

1,048,218

Warrants exercise price per share

$ 4.77

Amount of warrants aggregate exercise price

$ 5,000,000

Warrants expiry term

2 years

Class B common stock | Subsequent Event [Member] | Investor [Member]

Equity (Textual)

Sale of shares

230,415

Warrants to purchase shares

209,644

Warrants of sale price

10.00%

Series 2012-A Preferred Stock [Member]

Equity (Textual)

Preferred stock, liquidation preference per share

8.50

Preferred stock dividend rate

$ 0.6375

Preferred stock, dividend payment rate, variable

Seven and one-half percent (7.5%) of the quotient obtained by dividing (A) the amount by which the EBITDA for a fiscal year of the Company's retail energy provider business exceeds $32 million by (B) 8,750,000 (the "Additional Dividend").

Preferred stock, redemption terms

The Preferred Stock is redeemable, in whole or in part, at the option of the Company following October 11, 2017 at 101% of the Liquidation Preference plus accrued and unpaid dividends, and 100% of the Liquidation Preference plus accrued and unpaid dividends following October 11, 2018.

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - Restricted Stock [Member] shares in Thousands	12 Months Ended
	Dec. 31, 2017$ / sharesshares
Summary of the status of the Company's grants of restricted shares of Class B common stock
Beginning balance, Number of Non-vested Shares | shares	26
Number of Non-vested Shares, Granted | shares	182
Number of Non-vested Shares, Vested | shares	(45)
Number of Non-vested Shares, Forfeited | shares
Ending balance, Number of Non-vested Shares | shares	163
Beginning balance, Weighted- Average Grant Date Fair Value | $ / shares	$ 10.08
Weighted- Average Grant Date Fair Value, Granted | $ / shares	5.77
Weighted- Average Grant Date Fair Value, Vested | $ / shares	8.36
Weighted- Average Grant Date Fair Value, Forfeited | $ / shares
Ending balance, Weighted- Average Grant Date Fair Value | $ / shares	$ 6.19

Stock-Based Compensation (Det81

Stock-Based Compensation (Details 1) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Equity compensation plans, valuation assumptions
Average risk-free interest rate	0.40%	0.93%
Expected dividend yield	5.01%
Expected volatility	55.50%	61.00%
Expected term	1 year	5 years 6 months
Weighted-average grant date fair value of options granted	$ 1.05	$ 9.67

Stock-Based Compensation (Det82

Stock-Based Compensation (Details 2) - Stock options [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Summary of stock option activity
Number of Options, Outstanding, Beginning Balance	414
Number of Options, Granted
Number of Options, Exercised	(16)
Number of Options, Cancelled/Forfeited	(15)
Number of Options, Outstanding, Ending Balance	383	414
Number of Options, Exercisable	327
Weighted-Average Exercise Price Outstanding, Beginning Balance	$ 6.75
Weighted-Average Exercise Price, Granted
Weighted-Average Exercise Price, Exercised	6.85
Weighted-Average Exercise Price, Cancelled/Forfeited	4.05
Weighted-Average Exercise Price Outstanding, Ending Balance	6.85	$ 6.75
Weighted-Average Exercise Price, Exercisable	$ 6.85
Weighted-Average Remaining Contractual Term, Outstanding	3 years 9 months 18 days	4 years 7 months 6 days
Weighted-Average Remaining Contractual Term, Exercisable	3 years 9 months 18 days
Aggregate Intrinsic Value, Outstanding		$ 37
Aggregate Intrinsic Value, Exercisable

Stock-Based Compensation (Det83

Stock-Based Compensation (Details Textual) $ in Thousands	1 Months Ended		12 Months Ended
	Aug. 31, 2016USD ($)	Aug. 31, 2015USD ($)	Dec. 31, 2017USD ($)Stockshares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares	May 05, 2015
Stock-Based Compensation (Textual)
Stock-based compensation			$ 5,213	$ 4,813	$ 5,229
Class B common stock issued for GRE deferred stock units			1,845
Cash payment for subsidiary equity grant				1,688	1,200
GRE [Member]
Stock-Based Compensation (Textual)
Deferred stock units included in "Other current liabilities"			800	700
Cash payment for subsidiary equity grant	$ 1,700
Officers and employees [Member]
Stock-Based Compensation (Textual)
Ownership interest of company						3.90%
Restricted Stock Granted [Member]
Stock-Based Compensation (Textual)
Total grant date fair value of shares vested			400	500	500
Stock-based compensation			3,100	3,500	3,600
Stock options [Member]
Stock-Based Compensation (Textual)
Total unrecognized compensation cost			$ 100
Period of unrecognized compensation cost expected to be recognized			1 year 1 month 6 days
Stock-based compensation			$ 35	23	300
Total intrinsic value of options exercised			13		12
Other Subsidiary Equity [Member]
Stock-Based Compensation (Textual)
Total unrecognized compensation cost			$ 1,000
Period of unrecognized compensation cost expected to be recognized			4 months 24 days
Stock-based compensation			$ 2,100	$ 600	$ 1,400
Fair value of the deferred stock units grants			$ 3,300
Common Class B [Member]
Stock-Based Compensation (Textual)
Shares issued restricted stock award (Shares) | shares | shares				35,000	36,000
Class B common stock issued for GRE deferred stock units, Shares | shares			287,000
Common Class B [Member] | Restricted Stock [Member]
Stock-Based Compensation (Textual)
Total unrecognized compensation cost			$ 3,700
Period of unrecognized compensation cost expected to be recognized			9 months 18 days
Deferred Stock [Member] | IDT [Member]
Stock-Based Compensation (Textual)
Vested deferred stock units of IDT Energy | Stock			26.1
Cash payment for subsidiary equity grant		$ 1,200
2011 Stock Option and Incentive Plan [Member]
Stock-Based Compensation (Textual)
Shares available for future grants, Shares | shares			51,000
2011 Stock Option and Incentive Plan [Member] | Common Class B [Member]
Stock-Based Compensation (Textual)
Common stock reserved for future issuance | shares			1,300,000

Variable Interest Entity (Detai

Variable Interest Entity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity [Abstract]
Net income (loss)	$ 112	$ (1,136)	$ 34
Aggregate funding repaid to (provided by) the Company, net	$ 158	$ (871)	$ 950

Variable Interest Entity (Det85

Variable Interest Entity (Details 1) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Summarized consolidated balance sheet amounts related to CCE
TOTAL ASSETS	$ 2,035	$ 2,090
TOTAL LIABILITIES AND NONCONTROLLING INTERESTS	2,035	2,090
Cash and cash equivalents [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL ASSETS	52	150
Restricted cash [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL ASSETS	31	17
Trade accounts receivable [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL ASSETS	1,031	1,008
Prepaid expenses [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL ASSETS	451	450
Other current assets [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL ASSETS	31	26
Other assets [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL ASSETS	439	439
Current liabilities [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL LIABILITIES AND NONCONTROLLING INTERESTS	698	707
Due to IDT Energy [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL LIABILITIES AND NONCONTROLLING INTERESTS	1,140	1,298
Noncontrolling interests [Member]
Summarized consolidated balance sheet amounts related to CCE
TOTAL LIABILITIES AND NONCONTROLLING INTERESTS	$ 197	$ 85

Variable Interest Entity (Det86

Variable Interest Entity (Details Textual) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Variable Interest Entity (Textual)
Loan amount		$ 158	$ (871)	$ 950
CCE [Member]
Variable Interest Entity (Textual)
Payment to owner of limited liability company	$ 200
Loan amount	500
Variable interest entity, description		GRE paid $0.2 million to the owner of the limited liability company interests in CCE, and loaned CCE $0.5 million in exchange for an option to purchase 100% of the issued and outstanding limited liability company interests of CCE for one dollar plus the forgiveness of the $0.5 million loan.
Forgiveness of loan	$ 500
Options expiration date	Oct. 22, 2023

Accumulated Other Comprehensi87

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of accumulated balances for other comprehensive (loss) income
Accumulated other comprehensive income, Foreign currency translation, Beginning balance	$ 1,465	$ 154	$ 10
Other comprehensive income attributable to Genie, Foreign currency translation	1,580	1,311	144
Accumulated other comprehensive income, Foreign currency translation, Ending balance	$ 3,045	$ 1,465	$ 154

Legal and Regulatory Proceedi88

Legal and Regulatory Proceedings (Details) $ in Thousands		1 Months Ended	3 Months Ended			12 Months Ended
		Jul. 31, 2016USD ($)	Mar. 31, 2018MeterRCEs	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Legal and Regulatory Proceedings (Textual)
Proposed regulatory matter potential requirements, Description						The PSC's order, which were to become effective March 4, 2016, would require that all REPs' electricity and natural gas offerings to residential and small business customers include an annual guarantee of savings compared to the price charged by the relevant incumbent utility or, for electricity offerings, provide at least 30% of the supply from renewable sources.
Additional refunds to customers		$ 2,400
Total settlement payment					$ 9,000
Total payments reasonable settlement						$ 10,100
Revenue reduction					$ 3,600
Selling, general and administrative expense	[1]					80,122	$ 61,569	$ 66,011
Accrued expenses						28,069	$ 16,301
2016 Order [Member] | Subsequent Event [Member]
Legal and Regulatory Proceedings (Textual)
Number of meters transferred to incumbent utilities | Meter			21,000
RCEs transferred to incumbent utilities | RCEs			12,000
Settlement Agreement [Member]
Legal and Regulatory Proceedings (Textual)
Revenue reduction						3,600
Selling, general and administrative expense						5,400
Accrued expenses						9,000
New Jersey Office and Attorney General [Member]
Legal and Regulatory Proceedings (Textual)
Total payments reasonable settlement						$ 1,500
Revenue reduction				$ 1,300
Selling, general and administrative expense				200
Accrued expenses				$ 1,500
New York PSC [Member]
Legal and Regulatory Proceedings (Textual)
Percentage of GRE's total meters served						36.00%
Percentage of total RCEs of GRE's customer base						28.00%
[1]	Stock-based compensation included in selling, general and administrative expenses

Commitments and Contingencies89

Commitments and Contingencies (Details) $ in Thousands	Dec. 31, 2017USD ($)
Future minimum payments for operating leases
2,018	$ 193
2,019	77
2,020	41
2,021
2,022
Thereafter
Total payments	$ 311

Commitments and Contingencies90

Commitments and Contingencies (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies (Textual)
Purchase and other commitments	$ 46.4
Rental expense and operating leases	0.8	$ 0.7	$ 1.2
Purchase commitment due in December 31, 2018	43.2
Purchase commitment due in December 31, 2019	3.2
Future purchases of electricity	45
Genie Retail Energy [Member]
Commitments and Contingencies (Textual)
Aggregate performance bond outstanding	11.8
Purchase of renewable energy credit	15.6
BP [Member]
Commitments and Contingencies (Textual)
Payment of trade accounts payable to BP Energy	$ 13.8
Agreement termination, Description	The agreement's termination date is November 30, 2019, except either party may terminate the agreement on November 30, 2018 by giving the other party notice by May 31, 2018.
Trade Accounts Receivable [Member]
Commitments and Contingencies (Textual)
Assets pledged as collateral to BP Energy	$ 34.4
Restricted Cash [Member]
Commitments and Contingencies (Textual)
Assets pledged as collateral to BP Energy	$ 0.5

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of related party transactions
Amount IDT charged the Company	$ 1,773	$ 2,197	$ 2,340
Amount the Company charged IDT	$ 471	$ 627	$ 546

Related Party Transactions (D92

Related Party Transactions (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transactions (Textual)
Notes receivable outstanding from employees	$ 600,000	$ 1,000,000
Commissions and fees payments to related party	20,060	18,164	$ 14,236
Total payments for various insurance policies	20,060	18,657	$ 143,367
Commissions and fees paid to IGM	$ 201,565	$ 144,110

Business Segment and Geograph93

Business Segment and Geographic Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating results for the business segments
Revenues	$ 264,202	$ 212,112	$ 213,056
Income (loss) from operations	(6,540)	(30,513)	(8,329)
Depreciation and amortization	2,140	581	428
Research and development		(269)	1,985
Exploration	4,879	6,088	6,583
Write-off of capitalized exploration costs	6,483	41,041
Equity in the net loss of Shoreditch	565	222	397
GRE [Member]
Operating results for the business segments
Revenues	264,202	212,112	213,056
Income (loss) from operations	16,586	26,503	11,095
Depreciation and amortization	1,740	427	245
Research and development
Exploration
Equity in the net loss of Shoreditch	565
Afek [Member]
Operating results for the business segments
Revenues
Income (loss) from operations	(12,698)	(48,272)	(7,458)
Depreciation and amortization	327	124	104
Research and development			63
Exploration	4,879	6,088	6,583
Write-off of capitalized exploration costs	6,483	41,041
Equity in the net loss of Shoreditch
GOGAS [Member]
Operating results for the business segments
Revenues
Income (loss) from operations	(593)	439	(3,058)
Depreciation and amortization	72	29	78
Research and development		(269)	1,922
Exploration
Write-off of capitalized exploration costs
Equity in the net loss of Shoreditch		222	397
Corporate [Member]
Operating results for the business segments
Revenues
Income (loss) from operations	(9,835)	(9,183)	(8,908)
Depreciation and amortization	1	1	1
Research and development
Exploration
Write-off of capitalized exploration costs
Equity in the net loss of Shoreditch

Business Segment and Geograph94

Business Segment and Geographic Information (Details 1) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary total assets for the business segments
Total assets:	$ 125,778	$ 121,813	$ 155,815
GRE [Member]
Summary total assets for the business segments
Total assets:	112,521	87,539	80,177
Afek [Member]
Summary total assets for the business segments
Total assets:	2,588	6,685	38,665
GOGAS [Member]
Summary total assets for the business segments
Total assets:	7,887	12,224	17,770
Corporate [Member]
Summary total assets for the business segments
Total assets:	$ 2,782	$ 15,365	$ 19,203

Business Segment and Geograph95

Business Segment and Geographic Information (Details 2) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net Long Lived Assets and Assets Held Outside Country [Abstract]
Long-lived assets, net	$ 4,048	$ 1,642	$ 1,409
Total assets	125,778	121,813	155,815
United States [Member]
Net Long Lived Assets and Assets Held Outside Country [Abstract]
Long-lived assets, net	696	1,060	763
Total assets	115,605	113,158	114,880
Foreign Countries [Member]
Net Long Lived Assets and Assets Held Outside Country [Abstract]
Long-lived assets, net	3,352	582	646
Total assets	$ 10,173	$ 8,655	$ 40,935

Business Segment and Geograph96

Business Segment and Geographic Information (Details Textual)	12 Months Ended
	Dec. 31, 2017Segment
Business Segment and Geographic Information (Textual)
Number of reportable segments	3
GEIC [Member]
Business Segment and Geographic Information (Textual)
Company's investment, ownership percentage in subsidiary	99.30%
GRE [Member]
Business Segment and Geographic Information (Textual)
Company's investment, ownership percentage in subsidiary	100.00%
Ownership interest of company	1.25%
GOGAS [Member]
Business Segment and Geographic Information (Textual)
Company's investment, ownership percentage in subsidiary	92.00%
Afek [Member]
Business Segment and Geographic Information (Textual)
Company's investment, ownership percentage in subsidiary	86.10%

Selected Quarterly Financial 97

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended											12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	Jun. 30, 2017	[2]	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	[1]	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Revenues												$ 264,202	$ 212,112	$ 213,056
Cost of revenues												178,693	135,172	146,409
Income (loss) from operations												(6,540)	(30,513)	(8,329)
Net (loss) income												(8,648)	(32,192)
Net income (loss) attributable to Genie Energy Ltd.												$ (6,994)	$ (24,525)	$ (7,457)
(Loss) earnings per common share, Basic												$ (0.36)	$ (1.14)	$ (0.40)
(Loss) earnings per common share, Diluted												$ (0.36)	$ (1.14)	$ (0.40)
Selected Quarterly Financial Data [Member]
Selected Quarterly Financial Information [Abstract]
Revenues	$ 73,077		$ 69,473	$ 50,247		$ 71,405	$ 51,519	$ 57,153		$ 44,561	$ 58,879
Cost of revenues	46,321		47,694	38,122		46,556	36,949	36,946		26,445	34,832
Income (loss) from operations	430		1,403	(13,569)		5,196	(1,344)	(37,102)		1,934	5,999
Net (loss) income	(812)		975	(12,950)		4,139	(1,285)	(37,174)		1,417	4,850
Net income (loss) attributable to Genie Energy Ltd.	$ 215		$ 778	$ (12,569)		$ 4,582	$ (816)	$ (32,139)		$ 2,761	$ 5,669
(Loss) earnings per common share, Basic	$ (0.01)		$ 0.02	$ (0.55)		$ 0.18	$ (0.05)	$ (1.43)		$ 0.10	$ 0.23
(Loss) earnings per common share, Diluted	$ (0.01)		$ 0.02	$ (0.55)		$ 0.18	$ (0.05)	$ (1.43)		$ 0.10	$ 0.22
[1]	In the fourth quarter of 2017 and in the third quarter of 2016, loss from operations included write-off of capitalized exploration costs of $6.5 million and $41.0 million, respectively.
[2]	In the second quarter of 2017, the Company recognized a liability of $9.0 million for the preliminary settlement of certain class action lawsuits. The Company recorded the liability as a revenue reduction of $3.6 million and an expense of $5.4 million.

Selected Quarterly Financial 98

Selected Quarterly Financial Data (Unaudited) (Details Textual) - USD ($) $ in Thousands		3 Months Ended				12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Data (Unaudited) (Textual)
Write-off of capitalized exploration costs						$ 6,483	$ 41,041
Settlement preliminary of liability				$ 9,000
Revenue reduction				3,600
Revenue expense				$ 5,400
Selling, General and Administrative Expense	[1]					80,122	61,569	$ 66,011
Accrued expenses		$ 28,069				$ 28,069	$ 16,301
New Jersey Office and Attorney General [Member]
Selected Quarterly Financial Data (Unaudited) (Textual)
Revenue reduction			$ 1,300
Selling, General and Administrative Expense			200
Accrued expenses			$ 1,500
Write-off of capitalized exploration costs [Member]
Selected Quarterly Financial Data (Unaudited) (Textual)
Write-off of capitalized exploration costs		$ 6,500			$ 41,000
[1]	Stock-based compensation included in selling, general and administrative expenses