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Acquired Business and Noncontrolling Interests - Additional Information (Detail) - USD ($)
6 Months Ended
Jun. 30, 2018
Dec. 30, 2017
Sep. 20, 2017
Jul. 01, 2017
Goodwill $ 38,704,000 $ 39,065,000   $ 31,134,000
Fletes Avella | Landstar Metro        
Business combination, recognized identifiable assets acquired and liabilities assumed, liabilities 700,000 $ 1,900,000    
Ownership interest acquired by affiliates     30.00%  
Goodwill $ 8,500,000      
Percentage of goodwill estimated to be deductible for tax purposes 70.00%      
Percentage of goodwill estimated to be deductible after purchase of noncontrolling interests by the company 100.00%      
Fletes Avella | Landstar Servicios        
Ownership interest acquired by affiliates     30.00%