Note 3 - Segment Information - Schedule of Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues:
Net sales	$ 392	$ 441
Net investment income	499	198
Net (losses) gains	(3)	345
Total revenues	888	984
Expenses:
Manufacturing cost of sales	204	192
Engineering, selling and administrative	605	542
Total expenses	809	734
Income (loss) from continuing operations before income taxes	79	250
Income tax expense	36	65
Net income (loss) from continuing operations	43	185
Income (loss) from discontinued operations, net of tax	0	(28)
Net income attributable to LGL Group or non-controlling interests	43	157
Less: Net income attributable to non-controlling interests	22	0
Net income (loss) attributable to LGL Group common stockholders	21	157
Operating Segments [Member] | Electronic Instruments [Member]
Revenues:
Net sales	392	441
Net investment income	0	0
Net (losses) gains	0	0
Total revenues	392	441
Expenses:
Manufacturing cost of sales	204	192
Engineering, selling and administrative	186	177
Total expenses	390	369
Income (loss) from continuing operations before income taxes	2	72
Income tax expense	0	0
Net income (loss) from continuing operations	2	72
Income (loss) from discontinued operations, net of tax	0	0
Net income attributable to LGL Group or non-controlling interests	2	72
Less: Net income attributable to non-controlling interests	0	0
Net income (loss) attributable to LGL Group common stockholders	2	72
Operating Segments [Member] | Merchant Investment [Member]
Revenues:
Net sales	0	0
Net investment income	289	0
Net (losses) gains	0	0
Total revenues	289	0
Expenses:
Manufacturing cost of sales	0	0
Engineering, selling and administrative	49	0
Total expenses	49	0
Income (loss) from continuing operations before income taxes	240	0
Income tax expense	0	0
Net income (loss) from continuing operations	240	0
Income (loss) from discontinued operations, net of tax	0	0
Net income attributable to LGL Group or non-controlling interests	240	0
Less: Net income attributable to non-controlling interests	22	0
Net income (loss) attributable to LGL Group common stockholders	218	0
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Revenues:
Net sales	0	0
Net investment income	210	198
Net (losses) gains	(3)	345
Total revenues	207	543
Expenses:
Manufacturing cost of sales	0	0
Engineering, selling and administrative	370	365
Total expenses	370	365
Income (loss) from continuing operations before income taxes	(163)	178
Income tax expense	36	65
Net income (loss) from continuing operations	(199)	113
Income (loss) from discontinued operations, net of tax	0	(28)
Net income attributable to LGL Group or non-controlling interests	(199)	85
Less: Net income attributable to non-controlling interests	0	0
Net income (loss) attributable to LGL Group common stockholders	$ (199)	$ 85