Schedule Of Revenue By Major Customers By Reporting Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 1,287,534	$ 927,566
BCO Independent Contractors – Truck
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	44.00%	46.00%
Brokerage Carriers - Truck
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	49.00%	46.00%
Rail Intermodal
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	2.00%	3.00%
Ocean and air cargo carriers
Disaggregation of Revenue [Line Items]
Percentage of Consolidated Revenue	4.00%	3.00%
BCO Independent Contractor Truck and Brokerage Carriers Truck | Van Equipment
Disaggregation of Revenue [Line Items]
Revenue	$ 827,187	$ 545,307
BCO Independent Contractor Truck and Brokerage Carriers Truck | Unsided/Platform Equipment
Disaggregation of Revenue [Line Items]
Revenue	340,632	286,328
BCO Independent Contractor Truck and Brokerage Carriers Truck | Less than Truckload
Disaggregation of Revenue [Line Items]
Revenue	$ 25,670	$ 22,941