Schedule Of Revenue By Major Customers By Reporting Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 1,570,718	$ 823,514	$ 2,858,252	$ 1,751,080
BCO Independent Contractors – Truck
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	41.00%	46.00%	42.00%	46.00%
Brokerage Carriers - Truck
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	51.00%	46.00%	50.00%	46.00%
Rail Intermodal
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	3.00%	3.00%	3.00%	3.00%
Ocean and air cargo carriers
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	4.00%	4.00%	4.00%	3.00%
BCO Independent Contractor Truck and Brokerage Carriers Truck | Van Equipment
Disaggregation of Revenue [Line Items]
Revenue	$ 970,874	$ 483,027	$ 1,798,061	$ 1,028,334
BCO Independent Contractor Truck and Brokerage Carriers Truck | Unsided/Platform Equipment
Disaggregation of Revenue [Line Items]
Revenue	444,251	247,388	784,883	533,716
BCO Independent Contractor Truck and Brokerage Carriers Truck | Less than Truckload
Disaggregation of Revenue [Line Items]
Revenue	$ 29,062	$ 22,918	$ 54,732	$ 45,859