Subsidiaries of the Registrant - Subsidiaries of the Company (Details)	3 Months Ended
	Mar. 31, 2019
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 Frequenc, 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%