Schedule of Carrying Amounts of Major classes of Assets and Liabilities Classified as Held-for-Sale (Parenthetical) (Details) - USD ($) $ in Thousands	Aug. 31, 2019	Aug. 31, 2018
Discontinued Operations And Disposal Groups [Abstract]
Receivables, allowance	$ 0	$ 244

Disposal group including discontinued operation allowance for accounts, notes and loans receivable.

No definition available.

Name:	lnn_DisposalGroupIncludingDiscontinuedOperationAllowanceForAccountsNotesAndLoansReceivable
Namespace Prefix:	lnn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant