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Accounting And Reporting Policies (Details) (USD $) | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2011
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Cash consideration | $ 700,000 us-gaap_PaymentsToAcquireBusinessesGross |  |
Property, Plant and Equipment, Net [Abstract] |  |  |
Depreciation expense | 821,000 us-gaap_Depreciation | 913,000 us-gaap_Depreciation |
Standard Product Warranty Disclosure [Abstract] |  |  |
Term of warranty | 1 year |  |
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] |  |  |
2015 | 54,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths |  |
2016 | 54,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo |  |
2017 | 54,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree |  |
2018 | 54,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour |  |
2019 | 54,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive |  |
Thereafter | 218,000 us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive |  |
Total | 488,000 us-gaap_FiniteLivedIntangibleAssetsNet |  |
Prior Year Reclassification [Abstract] |  |  |
Prior Year Reclassification |  | 76,000 lgl_PriorYearReclassification |
Intangible Assets [Abstract] |  |  |
Indefinite-Lived Intangible Assets (Excluding Goodwill) | 488,000 us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill | 36,000 us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill |
Goodwill | 40,000 us-gaap_Goodwill | 40,000 us-gaap_Goodwill |
Research and Development Costs [Abstract] |  |  |
Research and development costs | 2,166,000 us-gaap_ResearchAndDevelopmentExpense | 2,285,000 us-gaap_ResearchAndDevelopmentExpense |
Advertising Expense [Abstract] |  |  |
Advertising costs | 92,000 us-gaap_AdvertisingExpense | 90,000 us-gaap_AdvertisingExpense |
Stock-Based Compensation [Abstract] |  |  |
Forfeiture rate (in hundredths) |  | 5.00%lgl_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate |
Earnings Per Share [Abstract] |  |  |
Options excluded from the diluted earnings per share computation (in shares) | 218,667 us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount | 177,861 us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount |
Foreign Currency Translation [Abstract] |  |  |
Re-measurement loss | 44,000 us-gaap_ForeignCurrencyTransactionGainLossBeforeTax | (86,000)us-gaap_ForeignCurrencyTransactionGainLossBeforeTax |
Restructuring Charges [Abstract] |  |  |
Restructuring Charges | 465,000 us-gaap_RestructuringCharges | 648,000 us-gaap_RestructuringCharges |
Revenues [Member] | Customer Concentration Risk [Member] |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage (in hundredths) | 11.00%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueGoodsNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember | 10.80%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueGoodsNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember |
Revenue concentration greater than 10% | 2,522,000 lgl_RevenueConcentrationGreaterThan10 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueGoodsNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember | 2,840,000 lgl_RevenueConcentrationGreaterThan10 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_SalesRevenueGoodsNetMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember |
Accounts Receivable [Member] | Customer Concentration Risk [Member] |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage (in hundredths) | 31.30%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_AccountsReceivableMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember | 27.60%us-gaap_ConcentrationRiskPercentage1 / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_AccountsReceivableMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember |
Accounts receivable | 1,035,000 us-gaap_AccountsReceivableNet / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_AccountsReceivableMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember | 905,000 us-gaap_AccountsReceivableNet / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_AccountsReceivableMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember |
Number of large customers | 3 lgl_NumberOfLargeCustomers / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_AccountsReceivableMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember | 3 lgl_NumberOfLargeCustomers / us-gaap_ConcentrationRiskByBenchmarkAxis = us-gaap_AccountsReceivableMember / us-gaap_ConcentrationRiskByTypeAxis = us-gaap_CustomerConcentrationRiskMember |
Sale of Real Property Located in Bainbridge, Georgia [Member] |  |  |
Significant Acquisitions and Disposals [Line Items] |  |  |
Value of considerations received in sale |  |  | 322,610 us-gaap_SignificantAcquisitionsAndDisposalsAcquisitionCostsOrSaleProceeds / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = lgl_SaleOfRealPropertyLocatedInBainbridgeGeorgiaMember
Principal amount of promissory note |  | $ 237,612 us-gaap_NotesReceivableGross / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = lgl_SaleOfRealPropertyLocatedInBainbridgeGeorgiaMember | $ 322,610 us-gaap_NotesReceivableGross / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = lgl_SaleOfRealPropertyLocatedInBainbridgeGeorgiaMember
Interest rate of promissory note (in hundredths) |  | 3.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = lgl_SaleOfRealPropertyLocatedInBainbridgeGeorgiaMember | 7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_SignificantAcquisitionsAndDisposalsByTransactionAxis = lgl_SaleOfRealPropertyLocatedInBainbridgeGeorgiaMember
Maturity date of promissory note |  | Jul. 28, 2016 | Aug. 01, 2013
Minimum [Member] |  |  |
Stock-Based Compensation [Abstract] |  |  |
Forfeiture rate (in hundredths) | 0.00%lgl_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate / us-gaap_RangeAxis = us-gaap_MinimumMember | 0.00%lgl_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate / us-gaap_RangeAxis = us-gaap_MinimumMember |
Minimum [Member] | Buildings and Improvements [Member] |  |  |
Property, Plant and Equipment, Net [Abstract] |  |  |
Property, Plant and Equipment, Useful Life | 5 years |  |
Minimum [Member] | Other Fixed Assets [Member] |  |  |
Property, Plant and Equipment, Net [Abstract] |  |  |
Property, Plant and Equipment, Useful Life | 3 years |  |
Maximum [Member] |  |  |
Stock-Based Compensation [Abstract] |  |  |
Forfeiture rate (in hundredths) | 10.00%lgl_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate / us-gaap_RangeAxis = us-gaap_MaximumMember | 5.00%lgl_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsForfeitureRate / us-gaap_RangeAxis = us-gaap_MaximumMember |
Maximum [Member] | Buildings and Improvements [Member] |  |  |
Property, Plant and Equipment, Net [Abstract] |  |  |
Property, Plant and Equipment, Useful Life | 35 years |  |
Maximum [Member] | Other Fixed Assets [Member] |  |  |
Property, Plant and Equipment, Net [Abstract] |  |  |
Property, Plant and Equipment, Useful Life | 10 years |  |
M-tron Industries, Inc. [Member] |  |  |
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Owned by The LGL Group, Inc. (in hundredths) | 100.00%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = lgl_MTronIndustriesIncMember |  |
M-tron Industries, Ltd. [Member] |  |  |
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Owned by The LGL Group, Inc. (in hundredths) | 99.90%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = lgl_MTronIndustriesLtdMember |  |
Piezo Technology, Inc. [Member] |  |  |
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Owned by The LGL Group, Inc. (in hundredths) | 100.00%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = lgl_PiezoTechnologyIncMember |  |
Piezo Technology India Private Ltd. [Member] |  |  |
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Owned by The LGL Group, Inc. (in hundredths) | 99.00%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = lgl_PiezoTechnologyIndiaPrivateLtdMember |  |
M-tron Asia LLC [Member] |  |  |
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Owned by The LGL Group, Inc. (in hundredths) | 100.00%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = lgl_MTronAsiaLlcMember |  |
M-tron Services Ltd [Member] |  |  |
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Owned by The LGL Group, Inc. (in hundredths) | 100.00%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = lgl_MTronServicesLtdMember |  |
Lynch Systems, Inc. [Member] |  |  |
Subsidiaries of the entity, by ownership percentage [Abstract] |  |  |
Owned by The LGL Group, Inc. (in hundredths) | 100.00%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = lgl_LynchSystemsIncMember |  |

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