Note 3 - Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues:
Net sales	$ 650	$ 438	$ 1,573	$ 1,282
Net investment income	531	544	1,568	1,017
Net (losses) gains	(2)	(4)	(6)	384
Total revenues	1,179	978	3,135	2,683
Expenses:
Manufacturing cost of sales	368	195	786	595
Engineering, selling and administrative	673	584	1,895	1,771
Total expenses	1,041	779	2,681	2,366
Income (loss) from continuing operations before income taxes	138	199	454	317
Income tax expense	48	69	160	132
Net income (loss) from continuing operations	90	130	294	185
Income (loss) from discontinued operations, net of tax	0	0	0	(28)
Net income attributable to LGL Group or non-controlling interests	90	130	294	157
Less: Net income attributable to non-controlling interests	18	22	64	22
Net income (loss) attributable to LGL Group common stockholders	72	108	230	135
Operating Segments [Member] | Electronic Instruments [Member]
Revenues:
Net sales	650	438	1,573	1,282
Net investment income	0	0	0	0
Net (losses) gains	0	0	0	0
Total revenues	650	438	1,573	1,282
Expenses:
Manufacturing cost of sales	368	195	786	595
Engineering, selling and administrative	238	173	667	523
Total expenses	606	368	1,453	1,118
Income (loss) from continuing operations before income taxes	44	70	120	164
Income tax expense	0	0	0	0
Net income (loss) from continuing operations	44	70	120	164
Income (loss) from discontinued operations, net of tax	0	0	0	0
Net income attributable to LGL Group or non-controlling interests	44	70	120	164
Less: Net income attributable to non-controlling interests	0	0	0	0
Net income (loss) attributable to LGL Group common stockholders	44	70	120	164
Operating Segments [Member] | Merchant Investment [Member]
Revenues:
Net sales	0	0	0	0
Net investment income	318	287	922	542
Net (losses) gains	0	0	0	0
Total revenues	318	287	922	542
Expenses:
Manufacturing cost of sales	0	0	0	0
Engineering, selling and administrative	90	64	217	152
Total expenses	90	64	217	152
Income (loss) from continuing operations before income taxes	228	223	705	390
Income tax expense	0	0	0	0
Net income (loss) from continuing operations	228	223	705	390
Income (loss) from discontinued operations, net of tax	0	0	0	0
Net income attributable to LGL Group or non-controlling interests	228	223	705	390
Less: Net income attributable to non-controlling interests	18	22	64	22
Net income (loss) attributable to LGL Group common stockholders	210	201	641	368
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenues:
Net sales	0	0	0	0
Net investment income	213	257	646	475
Net (losses) gains	(2)	(4)	(6)	384
Total revenues	211	253	640	859
Expenses:
Manufacturing cost of sales	0	0	0	0
Engineering, selling and administrative	345	347	1,011	1,096
Total expenses	345	347	1,011	1,096
Income (loss) from continuing operations before income taxes	(134)	(94)	(371)	(237)
Income tax expense	48	69	160	132
Net income (loss) from continuing operations	(182)	(163)	(531)	(369)
Income (loss) from discontinued operations, net of tax	0	0	0	(28)
Net income attributable to LGL Group or non-controlling interests	(182)	(163)	(531)	(397)
Less: Net income attributable to non-controlling interests	0	0	0	0
Net income (loss) attributable to LGL Group common stockholders	$ (182)	$ (163)	$ (531)	$ (397)