XML 68 R57.htm IDEA: XBRL DOCUMENT v3.21.2

Donation - Additional Information (Details) - IronNet [Member] - Common Stock [Member] $ in Millions	Sep. 28, 2021 USD ($) shares
Donation Disclosure [Line Items]
Charitable gift | shares	50,000
Fair value of shares recognized, expense | $	$ 1,318,000

X

- Definition

Donation disclosure.

+ References

No definition available.

+ Details

Name:	lgl_DonationDisclosureLineItems
Namespace Prefix:	lgl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Fair value of shares recognized, expenses.

+ References

No definition available.

+ Details

Name:	lgl_FairValueOfSharesRecognizedExpenses
Namespace Prefix:	lgl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Number of shares issued as charitable gift.

+ References

No definition available.

+ Details

Name:	lgl_NumberOfSharesIssuedAsCharitableGift
Namespace Prefix:	lgl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Details

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

X

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: