Subsequent Events - Additional Information (Detail) - Subsequent Event [Member] $ in Thousands	1 Months Ended
	Apr. 30, 2020 USD ($) loads	May 15, 2020 loads
BCO Independent Contractor And Landstar Independent Commission Sales Agent [Member]
Subsequent Event [Line Items]
Extra Hauling Charges | $	$ 50
BCO Independent Contractor [Member]
Subsequent Event [Line Items]
Payment For Covid Ninteen Affected BCOs | $	$ 2,000
Minimum [Member] | BCO Independent Contractor [Member]
Subsequent Event [Line Items]
Number Of Loads Hauled | loads	60,000	30,000
Maximum [Member] | BCO Independent Contractor [Member]
Subsequent Event [Line Items]
Number Of Loads Hauled | loads	70,000	35,000