Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019	Dec. 28, 2019
Segment Reporting Information [Line Items]
External revenue	$ 1,085,546	$ 1,011,658	$ 2,836,626	$ 3,089,698
Internal revenue	9,078	9,611	44,912	36,978
Investment income	714	1,315	2,716	3,736
Operating income	82,352	70,638	168,538	232,385
Expenditures on long-lived assets	7,750	5,975	25,426	15,199
Goodwill	40,251	38,232	40,251	38,232	$ 38,508
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	1,071,374	997,552	2,795,056	3,047,329
Operating income	71,752	64,848	148,270	200,767
Expenditures on long-lived assets	7,750	5,975	25,426	15,199
Goodwill	40,251	38,232	40,251	38,232
Insurance
Segment Reporting Information [Line Items]
External revenue	14,172	14,106	41,570	42,369
Internal revenue	9,078	9,611	44,912	36,978
Investment income	714	1,315	2,716	3,736
Operating income	$ 10,600	$ 5,790	$ 20,268	$ 31,618