Schedule Of Revenue By Major Customers By Reporting Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 1,085,546	$ 1,011,658	$ 2,836,626	$ 3,089,698
BCO Independent Contractor - Truck
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	46.00%	46.00%	46.00%	45.00%
Brokerage Carriers - Truck
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	46.00%	46.00%	46.00%	47.00%
Rail Intermodal
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	3.00%	3.00%	3.00%	3.00%
Ocean and air cargo carriers
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	3.00%	3.00%	3.00%	3.00%
BCO Independent Contractor Truck and Brokerage Carriers Truck | Van Equipment
Disaggregation of Revenue [Line Items]
Revenue	$ 666,582	$ 575,042	$ 1,694,916	$ 1,799,421
BCO Independent Contractor Truck and Brokerage Carriers Truck | Unsided/Platform Equipment
Disaggregation of Revenue [Line Items]
Revenue	314,471	331,787	848,187	980,615
BCO Independent Contractor Truck and Brokerage Carriers Truck | Less than Truckload
Disaggregation of Revenue [Line Items]
Revenue	$ 25,125	$ 25,367	$ 70,984	$ 73,475