Leases - Classification on our Consolidated Balance Sheet (Detail) $ in Thousands	Dec. 26, 2020 USD ($)
Total lease assets	$ 141,854
Other Assets [Member]
Operating lease right-of-use assets	2,595
Property Plant and Equipment Net [Member]
Finance lease assets	$ 139,259

Represents aggregate of operating and finance lease right of use assets.

No definition available.

Name:	lstr_LeaseRightOfUseAsset
Namespace Prefix:	lstr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, after accumulated amortization, of right-of-use asset from finance lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121603541&loc=SL77918627-209977

+ Details

Name:	us-gaap_FinanceLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=lstr_PropertyPlantAndEquipmentNetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: