Cash collateral for line of credit.

No definition available.

Name:	gne_CashCollateralForLineOfCredit
Namespace Prefix:	gne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Loans payable basis spread on variable rate during period.

+ References

No definition available.

+ Details

Name:	gne_LoansPayableBasisSpreadOnVariableRateDuringPeriod
Namespace Prefix:	gne_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum amount collateral for line of credit under condition one.

+ References

No definition available.

+ Details

Name:	gne_MaximumAmountCollateralForLineOfCredit
Namespace Prefix:	gne_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	gne_RevolvingLineOfCreditTextualAbstract
Namespace Prefix:	gne_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Discussion of whether the borrowings under the credit facility are secured or unsecured and, if secured, a description of collateral (for example, accounts receivable less than 120 days old, finished goods inventory).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(b))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 22
-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityCollateral
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the frequency of the required periodic payments of interest, principal, or both, and the amount, if set, or a description of a formula upon which payment is based.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityFrequencyOfPaymentAndPaymentTerms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying value as of the balance sheet date of the noncurrent portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=28361426&loc=d3e1314-112600

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 10
-Section 45
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=28361426&loc=d3e1336-112600

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Line-of-Credit Arrangement
-URI http://asc.fasb.org/extlink&oid=6517033

+ Details

Name:	us-gaap_LongTermLineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=gne_GenieRetailEnergyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=gne_JpmorganMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Revolving Lines of Credit (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 17, 2015	Dec. 31, 2015	Dec. 31, 2014	Apr. 23, 2012
Revolving Lines of Credit (Textual)
Revolving credit loan payable		$ 2,000
Line of credit facility, amount outstanding		$ 7,700	$ 7,600
Genie Retail Energy [Member]
Revolving Lines of Credit (Textual)
Revolving credit loan payable	$ 2,000
Interest rate description on principal outstanding	Outstanding principal amount incurs interest at LIBOR plus 3.5% per annum. Interest is payable monthly and all outstanding principal and any accrued and unpaid interest is due on the maturity date of December 17, 2018.
Extended Maturity Date	Dec. 17, 2018
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 description on principal outstanding		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%
Extended Maturity Date		Apr. 30, 2016
Quarterly unused commitment fee		0.08%
Line of credit facility, frequency of payment and payment terms		Interest is payable at least every three months
Cash collateral for line of credit		$ 10,000