Note 17 - Quarterly Financial Data (Unaudited) - Schedule of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2025		Sep. 30, 2025		Jun. 30, 2025		Mar. 31, 2025		Dec. 31, 2024		Sep. 30, 2024		Jun. 30, 2024		Mar. 31, 2024		Dec. 31, 2025		Dec. 31, 2024
Net sales	$ 803		$ 661		$ 491		$ 498		$ 653		$ 650		$ 531		$ 392		$ 2,453		$ 2,226
Interest revenue (a)	410		442		428		417		503		531		538		499		1,697	[1]	2,071	[1]
Net gains	6		5		5		3		1		(2)		(1)		(3)		19		(5)
Total revenues	1,219		1,108		924		918		1,157		1,179		1,068		888		4,169		4,292
Manufacturing cost of sales	395		312		211		237		261		368		214		204		1,155		1,047
Engineering, selling and administrative	705		676		744		640		651		673		617		605		2,765		2,546
Total expenses	1,100		988		955		877		912		1,041		831		809		3,920		3,593
Income before income taxes	119	[2]	120	[2]	(31)	[2]	41	[2]	245		138		237		79		249		699
Income tax expense (benefit)	126		(674)		14		28		17		48		76		36		(506)		177
Net income	(7)		794		(45)		13		228		90		161		43		755		522
Less: Net income attributable to non-controlling interests	20		22		6		19		26		18		24		22		67		90
Net income attributable to LGL Group common stockholders	$ (27)		$ 772		$ (51)		$ (6)		$ 202		$ 72		$ 137		$ 21		$ 688		$ 432
Basic (a) (in dollars per share)	$ (0)	[2]	$ 0.15	[2]	$ (0.01)	[2]	$ (0)	[2]	$ 0.04	[2]	$ 0.01	[2]	$ 0.03	[2]	$ 0	[2]	$ 0.13		$ 0.08
Diluted (in dollars per share)	$ (0)	[2]	$ 0.14	[2]	$ (0.01)	[2]	$ (0)	[2]	$ 0.04	[2]	$ 0.01	[2]	$ 0.02	[2]	$ 0	[2]	$ 0.11		$ 0.08
Weighted average common shares outstanding - basic (in shares)	5,547,516	[2]	5,312,797	[2]	5,352,937	[2]	5,352,937	[2]	5,352,937		5,352,937		5,352,937		5,352,937		5,404,463		5,352,937
Diluted (in shares)	5,547,516		5,649,743		5,352,937		5,352,937		5,577,062		5,531,969		5,482,543		5,604,430		6,406,016		5,553,823

[1] Interest revenue is included in Net investment income on the Consolidated Statements of Operations.

[2] Basic and diluted earnings per share are calculated using actual, unrounded amounts. Therefore, the quarterly earnings per share may not sum to the earnings per share on the Consolidated Statements of Operations.