Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Disaggregation of Revenue [Line Items]
Revenue	$ 823,514,000	$ 1,045,040,000	$ 1,751,080,000	$ 2,078,040,000
BCO Independent Contractor
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	46.00%	45.00%	46.00%	44.00%
Truck Brokerage Carriers
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	46.00%	47.00%	46.00%	48.00%
Railroads
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	3.00%	3.00%	3.00%	3.00%
Air and Ocean Cargo Carriers
Disaggregation of Revenue [Line Items]
Consolidated revenue, percentage	4.00%	3.00%	3.00%	3.00%
BCO Independent Contractor and Truck Brokerage Carriers | Van Equipment
Disaggregation of Revenue [Line Items]
Revenue	$ 483,027,000	$ 605,365,000	$ 1,028,334,000	$ 1,224,379,000
BCO Independent Contractor and Truck Brokerage Carriers | Unsided/Platform Equipment
Disaggregation of Revenue [Line Items]
Revenue	247,388,000	338,107,000	533,716,000	648,828,000
BCO Independent Contractor and Truck Brokerage Carriers | Less than Truckload
Disaggregation of Revenue [Line Items]
Revenue	$ 22,918,000	$ 24,732,000	$ 45,859,000	$ 48,108,000