Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2025	Sep. 28, 2024	Sep. 27, 2025	Sep. 28, 2024	Dec. 28, 2024
Segment Reporting Information [Line Items]
Revenue	$ 1,205,406	$ 1,213,867	$ 3,569,291	$ 3,609,915
Gross revenue	1,216,423	1,225,932	3,633,401	3,675,326
Investment income	3,293	3,922	10,620	10,988
Purchased transportation	936,472	943,805	2,775,761	2,799,384
Commissions to agents	98,693	98,703	291,529	295,801
Other operating costs, net of gains on asset sales/dispositions	15,572	15,144	46,996	44,138
Insurance and claims	44,025	42,463	167,419	149,241
Selling, general and administrative	57,015	51,252	174,303	162,613
Depreciation and amortization	11,509	15,371	35,884	44,001
Impairment of intangible and other assets	30,104	0	30,104	0
Operating income	26,326	63,116	122,025	191,136
Goodwill	34,005	41,122	34,005	41,122	$ 40,933
Interest and debt expense (income)	217	(1,169)	756	(4,455)
Income before income taxes	26,109	64,285	121,269	195,591
Related Party [Member]
Segment Reporting Information [Line Items]
Revenue	11,017	12,065	64,110	65,411
Transportation Logistics
Segment Reporting Information [Line Items]
Revenue	1,190,802	1,198,334	3,525,234	3,561,941
Gross revenue	1,190,802	1,198,334	3,525,234	3,561,941
Purchased transportation	936,472	943,805	2,775,761	2,799,384
Commissions to agents	98,693	98,703	291,529	295,801
Other operating costs, net of gains on asset sales/dispositions	15,572	15,144	46,996	44,138
Insurance and claims	26,014	29,592	89,387	84,429
Selling, general and administrative	53,875	48,101	165,860	153,118
Depreciation and amortization	11,509	15,371	35,884	44,001
Impairment of intangible and other assets	30,104		30,104
Operating income	18,563	47,618	89,713	141,070
Goodwill	34,005	41,122	34,005	41,122
Insurance
Segment Reporting Information [Line Items]
Revenue	14,604	15,533	44,057	47,974
Gross revenue	25,621	27,598	108,167	113,385
Investment income	3,293	3,922	10,620	10,988
Insurance and claims	18,011	12,871	78,032	64,812
Selling, general and administrative	3,140	3,151	8,443	9,495
Operating income	7,763	15,498	32,312	50,066
Insurance | Related Party [Member]
Segment Reporting Information [Line Items]
Revenue	$ 11,017	$ 12,065	$ 64,110	$ 65,411