Discontinued Operations - Summary of Carrying Value of Assets and Liabilities Classified as Discontinued Operations (Parenthetical) (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Discontinued Operations And Disposal Groups [Abstract]
Accounts receivable, allowances	$ 131

Disposal group, including discontinued operation, accounts receivable, allowance for credit loss.

No definition available.

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