Amount of funds invested in mutual funds.

No definition available.

Name:	lgl_FundsInvestedInMutualFunds
Namespace Prefix:	lgl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of income from mutual funds.

+ References

No definition available.

+ Details

Name:	lgl_IncomeFromMutualFunds
Namespace Prefix:	lgl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage of investment expense rate.

+ References

No definition available.

+ Details

Name:	lgl_InvestmentExpenseRate
Namespace Prefix:	lgl_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of monthly payment.

+ References

No definition available.

+ Details

Name:	lgl_MonthlyPayment
Namespace Prefix:	lgl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of shares distribution under spinoff.

+ References

No definition available.

+ Details

Name:	lgl_PercentageOfSharesDistributionUnderSpinoff
Namespace Prefix:	lgl_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of salaries and benefits reimbursed.

+ References

No definition available.

+ Details

Name:	lgl_SalariesAndBenefitsReimbursed
Namespace Prefix:	lgl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount, before refund, of cash paid to foreign, federal, state, and local jurisdictions as income tax.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482913/230-10-50-2A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 23
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-23

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482685/740-10-50-22

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25

+ Details

Name:	us-gaap_IncomeTaxesPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The cash outflow to acquire an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among myriad other features and characteristics.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

Name:	us-gaap_PaymentsToAcquireNotesReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of transactions with related party during the financial reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 850
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483326/850-10-50-1

+ Details

Name:	us-gaap_RelatedPartyTransactionAmountsOfTransaction
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=lgl_GamcoInvestorsIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=lgl_MtronptiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=lgl_TransitionalAdministrativeAndManagementServicesAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionAxis=lgl_TaxIndemnityAndSharingAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=lgl_AlphaGInvestmentManagementIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=lgl_SkylineSPVMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=lgl_SkylineSPVMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=lgl_SkylineNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 7 - Related Party Transactions (Details Textual) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025	Mar. 31, 2025	Oct. 07, 2022
Income Tax Paid, before Refund Received				$ 78	$ 47
Payments to Acquire Notes Receivable				$ 1,968	$ (0)
GAMCO Investors, Inc. [Member]
Investment Expense Rate		0.08%	0.08%	0.08%	0.08%
Funds Invested in Mutual Funds	$ 41,536	$ 41,536		$ 41,536		$ 36,175
Income From Mutual Funds		370	$ 366	716	$ 714
MtronPTI [Member]
Percentage of Shares Distribution Under Spinoff								100.00%
Salaries and Benefits Reimbursed		28	56	10	16
MtronPTI [Member] \| Transitional Administrative and Management Services Agreement [Member]
Monthly Payment							$ 4
MtronPTI [Member] \| Tax Indemnity and Sharing Agreement [Member]
Related Party Transaction, Amounts of Transaction		12	12	24	24
Income Tax Paid, before Refund Received		0	$ 0	0	$ 0
Alpha G Investment Management, Inc. [Member]
Salaries and Benefits Reimbursed		$ 66		$ 66
Skyline SPV [Member] \| Skyline SPV [Member] \| Skyline Note [Member]
Payments to Acquire Notes Receivable	$ 850