Subsidiaries of the Registrant - Subsidiaries of the Company (Details)	6 Months Ended
	Jun. 30, 2020
M-tron Systems Holdings, LLC [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
M-tron Industries, Inc. [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
Piezo Technology, Inc. [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
Piezo Technology India Private Ltd. [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	99.90%
M-tron Asia LLC [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
M-tron Industries, Ltd. [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
GC Opportunities Ltd. [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
M-tron Services Ltd [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
Precise Time and Frequency, LLC [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
Lynch Systems, Inc. [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	100.00%
LGL Systems Acquisition Holding Company, LLC [Member]
Subsidiaries Of Entity By Ownership Percentage [Abstract]
Owned by The LGL Group, Inc.	62.20%	[1]

[1] Accounted for as an equity method investment