Leases - Components of Lease Cost for Finance Leases and Operating Leases (Detail) $ in Thousands	6 Months Ended
Jun. 29, 2019 USD ($)
Finance leases:
Amortization of right-of-use assets	$ 13,132
Interest on lease liability	1,928
Total finance lease cost	15,060
Operating leases:
Lease cost	2,280
Sublease income	(2,571)
Total operating lease (income)/cost	(291)
Total lease cost	$ 14,769

Represents total finance lease cost.

No definition available.

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Namespace Prefix:	lstr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents total cost of operating and finance lease.

+ References

No definition available.

+ Details

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Namespace Prefix:	lstr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents operating lease cost abstract

+ References

No definition available.

+ Details

Name:	lstr_OperatingLeaseCostAbstract
Namespace Prefix:	lstr_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Rental income for the reporting period under operating leases net of related rental income expense.

+ References

No definition available.

+ Details

Name:	lstr_OperatingLeasesRentIncomeExpenseNet
Namespace Prefix:	lstr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_FinanceLeaseCostAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of interest expense on finance lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918638-209977

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971

+ Details

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

- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

+ Details

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

- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=77888399&loc=SL77918982-209971

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918686-209980

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of sublease income excluding finance and operating lease expense.

+ References

+ Details

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