Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 28, 2024	Dec. 30, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenue		$ 4,819,245	$ 5,303,322	$ 7,436,562
Gross revenue		4,876,721	5,371,299	7,515,791
Elimination of internal revenue		(57,476)	(67,977)	(79,229)
Total consolidated revenue		4,819,245	5,303,322	7,436,562
Investment income		14,810	10,141	3,162
Purchased transportation		3,745,241	4,068,262	5,804,017
Commissions to agents		392,751	462,668	614,865
Other operating costs, net of gains on asset sales/dispositions		58,781	54,191	45,192
Insurance and claims		171,405	182,218	205,064
Selling, general and administrative		217,708	211,799	221,279
Depreciation and amortization		56,738	58,153	57,453
Operating income		248,907	344,149	571,083
Interest and debt (income) expense	[1]	(5,419)	(3,946)	3,620
Income before income taxes		254,326	348,095	567,463
Goodwill		40,933	42,275	41,220
Related Party [Member]
Segment Reporting Information [Line Items]
Revenue		57,476	67,977	79,229
Total consolidated revenue		57,476	67,977	79,229
Transportation Logistics
Segment Reporting Information [Line Items]
Revenue		4,756,008	5,230,846	7,358,008
Gross revenue		4,756,008	5,230,846	7,358,008
Total consolidated revenue		4,756,008	5,230,846	7,358,008
Purchased transportation		3,745,241	4,068,262	5,804,017
Commissions to agents		392,751	462,668	614,865
Other operating costs, net of gains on asset sales/dispositions		58,781	54,191	45,192
Insurance and claims		92,712	101,179	105,477
Selling, general and administrative		204,089	197,819	206,504
Depreciation and amortization		56,738	58,153	57,453
Operating income		205,696	288,574	524,500
Goodwill		40,933	42,275	41,220
Transportation Logistics | Related Party [Member]
Segment Reporting Information [Line Items]
Revenue		0	0	0
Total consolidated revenue		0	0	0
Insurance
Segment Reporting Information [Line Items]
Revenue		63,237	72,476	78,554
Gross revenue		120,713	140,453	157,783
Total consolidated revenue		63,237	72,476	78,554
Investment income		14,810	10,141	3,162
Insurance and claims		78,693	81,039	99,587
Selling, general and administrative		13,619	13,980	14,775
Operating income		43,211	55,575	46,583
Insurance | Related Party [Member]
Segment Reporting Information [Line Items]
Revenue		57,476	67,977	79,229
Total consolidated revenue		$ 57,476	$ 67,977	$ 79,229

[1] Interest and debt (income) expense includes (1) interest income earned on cash balances held by the transportation logistics segment of $9,495, $7,811 and $900 in 2024, 2023 and 2022, respectively and (2) consolidated total interest expense of $4,076, $3,865 and $4,520 (1) in 2024, 2023 and 2022, respectively.