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Acquired Business and Noncontrolling Interests - Additional Information (Detail) - USD ($)		12 Months Ended
	Sep. 20, 2017	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Goodwill		$ 38,232,000	$ 39,065,000	$ 31,134,000
Contigent consideration liability remitted		$ 1,000,000
Approximate percentage of voting rights acquired		9.00%
Consideration paid to purchase remaining equity interest		$ 600,000
Fletes Avella
Contigent consideration liability negated		$ 900,000
Fletes Avella | Landstar Metro
Payments to acquire businesses, gross	$ 8,460,000
Business combination, recognized identifiable assets acquired and liabilities assumed, liabilities			1,900,000
Approximate ownership interest acquired by affiliates		21.00%
Goodwill		$ 7,900,000
Percentage of goodwill estimated to be deductible after purchase of noncontrolling interests by the company		100.00%
One-time costs related to completion of acquisition			$ 1,000,000
One-time costs related to completion of acquisition, per share			$ 0.01
One-time costs related to completion of acquisition, per share diluted			$ 0.01
Fletes Avella | Landstar Servicios
Approximate ownership interest acquired by affiliates		21.00%

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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