Note 9 - Investments - Schedule of Equity Securities without Readily Determinable Fair Value (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024
Balance, beginning of period	$ 10,634	$ 4,835
Purchase	3,500	3,025
Gain recognized during the period	806	365
Distribution	(902)	(582)
Balance, end of period	$ 14,038	$ 7,643

Relates to payments or distribution of equity securities

No definition available.

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Namespace Prefix:	gne_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash outflow to acquire investment in equity security measured at fair value.

+ References

No definition available.

+ Details

Name:	gne_PaymentsToAcquireEquitySecuritiesWithoutReadilyDeterminableFairValueAmount
Namespace Prefix:	gne_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479536/321-10-50-3

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of gain from upward price adjustment on investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479536/321-10-50-3

+ Details

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Data Type:	xbrli:monetaryItemType
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