Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020	Dec. 26, 2020
Segment Reporting Information [Line Items]
External revenue	$ 1,734,299	$ 1,085,546	$ 4,592,551	$ 2,836,626
Internal revenue	9,533	9,078	53,028	44,912
Investment income	706	714	2,138	2,716
Operating income	131,412	82,352	356,928	168,538
Expenditures on long-lived assets	9,561	7,750	18,561	25,426
Goodwill	40,980	40,251	40,980	40,251	$ 40,949
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	1,716,004	1,071,374	4,539,561	2,795,056
Operating income	123,410	71,752	323,370	148,270
Expenditures on long-lived assets	9,561	7,750	18,561	25,426
Goodwill	40,980	40,251	40,980	40,251
Insurance
Segment Reporting Information [Line Items]
External revenue	18,295	14,172	52,990	41,570
Internal revenue	9,533	9,078	53,028	44,912
Investment income	706	714	2,138	2,716
Operating income	$ 8,002	$ 10,600	$ 33,558	$ 20,268