Note 18 - Business Segment Information - Schedule of Operating Results (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenues	$ 105,251	$ 90,696	$ 242,058	$ 210,384
Cost of revenues	81,771	57,360	181,215	143,262
Gross profit	23,480	33,336	60,843	67,122
Marketing and customer acquisition expenses	8,421	8,588	17,282	17,282
Employee-related expenses	6,139	6,619	12,886	13,518
Provision for credit losses	547	481	856	1,210
Stock-based compensation	606	458	1,345	1,207
Depreciation and amortization	236	196	470	415
Provision for captive insurance liability	265	640	910	1,676
Impairment of assets	35	118	35	118
Other selling, general and administrative expenses	5,228	5,673	12,225	11,284
Income (loss) from operations	2,003	10,563	14,834	20,412
Provision for (benefit from) income taxes	1,079	3,465	5,458	6,385
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenues	0	0	0	0
Cost of revenues	0	0	0	0
Gross profit	0	0	0	0
Marketing and customer acquisition expenses	0	0	0	19
Employee-related expenses	925	979	1,361	2,196
Provision for credit losses	0	0	0	0
Stock-based compensation	324	189	782	683
Depreciation and amortization	0	0	0	0
Provision for captive insurance liability	265	640	910	1,676
Impairment of assets	0	0	0	0
Other selling, general and administrative expenses	290	850	1,912	1,838
Income (loss) from operations	(1,804)	(2,658)	(4,965)	(6,412)
Provision for (benefit from) income taxes	(139)	(758)	(1,265)	(1,317)
Genie Retail Energy (“GRE”) [Member] | Operating Segments [Member]
Revenues	98,992	86,718	231,467	199,183
Cost of revenues	77,670	54,449	174,244	134,720
Gross profit	21,322	32,269	57,223	64,463
Marketing and customer acquisition expenses	8,257	8,443	16,926	16,961
Employee-related expenses	3,900	4,476	8,959	9,019
Provision for credit losses	547	481	856	1,210
Stock-based compensation	260	260	518	507
Depreciation and amortization	75	46	149	151
Provision for captive insurance liability	0	0	0	0
Impairment of assets	0	0	0	0
Other selling, general and administrative expenses	4,295	3,952	8,980	7,755
Income (loss) from operations	3,988	14,611	20,835	28,860
Provision for (benefit from) income taxes	1,380	4,454	7,118	8,543
Genie Renewables (GREW) [Member] | Operating Segments [Member]
Revenues	6,259	3,978	10,591	11,201
Cost of revenues	4,101	2,911	6,971	8,542
Gross profit	2,158	1,067	3,620	2,659
Marketing and customer acquisition expenses	164	145	356	302
Employee-related expenses	1,314	1,164	2,566	2,303
Provision for credit losses	0	0	0	0
Stock-based compensation	22	9	45	17
Depreciation and amortization	161	150	321	264
Provision for captive insurance liability	0	0	0	0
Impairment of assets	35	118	35	118
Other selling, general and administrative expenses	643	871	1,333	1,691
Income (loss) from operations	(181)	(1,390)	(1,036)	(2,036)
Provision for (benefit from) income taxes	$ (162)	$ (231)	$ (395)	$ (841)