Note 12 - Earnings Per Common Share - Reconciliation of Basic to Diluted Weighted Average Shares Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2023		Sep. 30, 2023		Jun. 30, 2023		Mar. 31, 2023		Dec. 31, 2022		Sep. 30, 2022		Jun. 30, 2022		Mar. 31, 2022		Dec. 31, 2023	Dec. 31, 2022
Income (loss) from continuing operations	$ 160		$ 130		$ (130)		$ 185		$ 1	[1]	$ (1,984)	[1]	$ (2,255)	[1]	$ (639)	[1]	$ 345	$ (4,877)
Less: Net income from continuing operations attributable to non-controlling interests																	48	0
Income (loss) attributable to LGL Group common stockholders from continuing operations																	297	(4,877)
(Loss) income from discontinued operations, net of tax																	(28)	1,885
Net income (loss) attributable to LGL Group common stockholders																	$ 269	$ (2,992)
Weighted average common shares outstanding - basic (in shares)	5,352,937		5,352,937		5,352,937		5,352,937		5,349,187		5,346,043		5,334,187		5,323,973		5,352,937	5,338,417
Stock options (in shares)																	0	45,249
Weighted average common shares outstanding - diluted (in shares)	5,381,685		5,355,006		5,352,937		5,352,937		5,356,188		5,346,043		5,334,187		5,345,202		5,352,937	5,383,666
Income (loss) from continuing operations (in dollars per share)	$ 0.03	[1]	$ 0.02	[1]	$ (0.02)	[1]	$ 0.03	[1]	$ 0	[1]	$ (0.37)	[1]	$ (0.42)	[1]	$ (0.12)	[1]	$ 0.06	$ (0.91)
(Loss) income from discontinued operations (in dollars per share)	0	[1]	0	[1]	0	[1]	(0.01)	[1]	0.02	[1]	0.09	[1]	0.09	[1]	0.15	[1]	(0.01)	0.35
Net income (loss) attributable to LGL Group common stockholders (in dollars per share)	0.03	[1]	0.02	[1]	(0.02)	[1]	0.03	[1]	0.02	[1]	(0.28)	[1]	(0.34)	[1]	0.03	[1]	0.05	(0.56)
Income (loss) from continuing operations (in dollars per share)	0.02	[1]	0.02	[1]	(0.02)	[1]	0.03	[1]	0	[1]	(0.37)	[1]	(0.42)	[1]	(0.12)	[1]	0.06	(0.91)
(Loss) income from discontinued operations (in dollars per share)	0	[1]	0	[1]	0	[1]	(0.01)	[1]	0.02	[1]	0.09	[1]	0.09	[1]	0.15	[1]	(0.01)	0.35
Net income (loss) attributable to LGL Group common stockholders (in dollars per share)	$ 0.02	[1]	$ 0.02	[1]	$ (0.02)	[1]	$ 0.03	[1]	$ 0.02	[1]	$ (0.28)	[1]	$ (0.34)	[1]	$ 0.03	[1]	$ 0.05	$ (0.56)

[1] Basic and diluted earnings per share are calculated using actual, unrounded amounts. Therefore, (i) the components of earnings per share may not sum to its corresponding total or (ii) the quarterly earnings per share may not sum to the earnings per share on the Consolidated Statements of Operations.