Accounting And Reporting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 729,000	$ 699,000
Significant Acquisitions and Disposals [Line Items]
Recovery percentage of net proceeds from re-sale transaction of real property (in hundredths)	85.00%
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	10 years
Net carrying value of amortizable intangible assets	96,000	156,000
Goodwill	40,000	40,000
Estimated aggregate future amortization expense for intangible assets, excluding goodwill [Abstract]
2013	58,000
2014	38,000
Total	96,000	156,000
Research and Development Costs [Abstract]
Research and development costs	2,005,000	1,878,000
Advertising Expense [Abstract]
Advertising costs	42,000	99,000
Assumptions used in estimating fair value of stock options [Abstract]
Expected dividend rate (in hundredths)	0.00%	0.00%
Forfeiture rate (in hundredths)	0.00%	0.00%
Earnings Per Share [Abstract]
Options excluded from the diluted earnings per share computation (in shares)	130,000	90,000
Foreign Currency Translation [Abstract]
Re-measurement gain (loss)	(88,000)	(26,000)
Revenues [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	9.80%	10.30%
Revenue concentration greater than 10%	2,914,000	3,680,000
Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	42.40%	33.40%
Accounts receivable	1,880,000	1,441,000
Sale of real property located in Bainbridge, Georgia [Member]
Significant Acquisitions and Disposals [Line Items]
Value of considerations received in sale		322,610
Principal amount of promissory note		$ 322,610
Interest rate of promissory note (in hundredths)		7.00%
Maturity date of promissory note		Aug. 01, 2013
M-tron Industries, Inc. [Member]
Subsidiaries of the entity, by ownership percentage [Abstract]
Owned by The LGL Group, Inc. (in hundredths)	100.00%
M-tron Industries, Ltd. [Member]
Subsidiaries of the entity, by ownership percentage [Abstract]
Owned by The LGL Group, Inc. (in hundredths)	99.90%
Piezo Technology, Inc. [Member]
Subsidiaries of the entity, by ownership percentage [Abstract]
Owned by The LGL Group, Inc. (in hundredths)	100.00%
Piezo Technology India Private Ltd. [Member]
Subsidiaries of the entity, by ownership percentage [Abstract]
Owned by The LGL Group, Inc. (in hundredths)	99.00%
Lynch Systems, Inc. [Member]
Subsidiaries of the entity, by ownership percentage [Abstract]
Owned by The LGL Group, Inc. (in hundredths)	100.00%