Equity investment - Additional Information (Detail)	Apr. 01, 2022 USD ($)
Cavnue, LLC [Member] \| Landstar Investment Holdo LLC [Member]
Equity Securities without Readily Determinable Fair Value [Line Items]
Equity method investments	$ 4,999,000

Amount of investment in equity security without readily determinable fair value.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126980263&loc=SL75117539-209714

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