Note 3 - Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues:
Net sales	$ 531	$ 403	$ 923	$ 844
Net investment income	538	275	1,037	473
Net (losses) gains	(1)	43	(4)	388
Total revenues	1,068	721	1,956	1,705
Expenses:
Manufacturing cost of sales	214	208	418	400
Engineering, selling and administrative	617	645	1,222	1,187
Total expenses	831	853	1,640	1,587
Income (loss) from continuing operations before income taxes	237	(132)	316	118
Income tax (benefit) expense	76	(2)	112	63
Net income (loss) from continuing operations	161	(130)	204	55
Income (loss) from discontinued operations, net of tax	0	0	0	(28)
Net income attributable to LGL Group or non-controlling interests	161	(130)	204	27
Less: Net income attributable to non-controlling interests	24	0	46	0
Net income (loss) attributable to LGL Group common stockholders	137	(130)	158	27
Operating Segments [Member] | Electronic Instruments [Member]
Revenues:
Net sales	531	403	923	844
Net investment income	0	0	0	0
Net (losses) gains	0	0	0	0
Total revenues	531	403	923	844
Expenses:
Manufacturing cost of sales	214	208	418	400
Engineering, selling and administrative	243	173	429	350
Total expenses	457	381	847	750
Income (loss) from continuing operations before income taxes	74	22	76	94
Income tax (benefit) expense	0	0	0	0
Net income (loss) from continuing operations	74	22	76	94
Income (loss) from discontinued operations, net of tax	0	0	0	0
Net income attributable to LGL Group or non-controlling interests	74	22	76	94
Less: Net income attributable to non-controlling interests	0	0	0	0
Net income (loss) attributable to LGL Group common stockholders	74	22	76	94
Operating Segments [Member] | Merchant Investment [Member]
Revenues:
Net sales	0	0	0	0
Net investment income	315	0	604	0
Net (losses) gains	0	0	0	0
Total revenues	315	0	604	0
Expenses:
Manufacturing cost of sales	0	0	0	0
Engineering, selling and administrative	78	0	127	0
Total expenses	78	0	127	0
Income (loss) from continuing operations before income taxes	237	0	477	0
Income tax (benefit) expense	0	0	0	0
Net income (loss) from continuing operations	237	0	477	0
Income (loss) from discontinued operations, net of tax	0	0	0	0
Net income attributable to LGL Group or non-controlling interests	237	0	477	0
Less: Net income attributable to non-controlling interests	24	0	46	0
Net income (loss) attributable to LGL Group common stockholders	213	0	431	0
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenues:
Net sales	0	0	0	0
Net investment income	223	275	433	473
Net (losses) gains	(1)	43	(4)	388
Total revenues	222	318	429	861
Expenses:
Manufacturing cost of sales	0	0	0	0
Engineering, selling and administrative	296	472	666	837
Total expenses	296	472	666	837
Income (loss) from continuing operations before income taxes	(74)	(154)	(237)	24
Income tax (benefit) expense	76	(2)	112	63
Net income (loss) from continuing operations	(150)	(152)	(349)	(39)
Income (loss) from discontinued operations, net of tax	0	0	0	(28)
Net income attributable to LGL Group or non-controlling interests	(150)	(152)	(349)	(67)
Less: Net income attributable to non-controlling interests	0	0	0	0
Net income (loss) attributable to LGL Group common stockholders	$ (150)	$ (152)	$ (349)	$ (67)