Note 11 - Earnings Per Share ("EPS") - Reconciliation of Basic to Diluted Weighted Average Shares Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Net income (loss)		$ 0	$ 794	$ (957)	$ 762
Less: Net income attributable to non-controlling interests		45	22	63	47
Net (loss) income attributable to LGL Group common stockholders		$ (45)	$ 772	$ (1,020)	$ 715
Weighted average common shares outstanding - basic (in shares)		10,960,348	5,371,308	7,958,795	5,415,721
Weighted average common shares outstanding - diluted (a) (in shares)	[1],[2]	10,960,348	5,708,254	7,958,795	5,738,317
Basic (in dollars per share)		$ (0)	$ 0.14	$ (0.13)	$ 0.13
Diluted (in dollars per share)		$ (0)	$ 0.14	$ (0.13)	$ 0.12
Warrants [Member]
Dilutive effects (in shares)	[1]	0	319,065	0	308,508
Restricted Stock [Member]
Dilutive effects (in shares)	[1]	0	17,881	0	14,088
Previously Reported [Member]
Weighted average common shares outstanding - basic (in shares)		10,942,500	5,312,797	7,906,071	5,356,726
Revision of Prior Period, Adjustment [Member]
Weighted average common shares outstanding - basic (in shares)	[2]	17,848	58,511	52,724	58,995
Basic (in dollars per share)			$ 0.15		$ 0.13
Diluted (in dollars per share)			$ 0.14		$ 0.12

[1] For the three and nine months ended September 30, 2026, weighted average shares used for calculating earnings per share excludes subscription rights to purchase 6,062,714 shares of common stock, stock options to purchase 200,000 shares of common stock, and 138,315 shares from restricted stock awards as the inclusion of these instruments would be anti-dilutive to the earnings per share calculation.

[2] Weighted average shares outstanding for the three and nine months ended September 30, 2026 and 2025 have been retroactively adjusted for the bonus element of the Rights Offering. Refer to "Rights Offering Bonus Element" below.