Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Dec. 28, 2019
Segment Reporting Information [Line Items]
External revenue	$ 823,514	$ 1,045,040	$ 1,751,080	$ 2,078,040
Internal revenue	26,755	17,753	35,834	27,367
Investment income	835	1,283	2,002	2,421
Operating income	32,181	80,851	86,186	161,747
Expenditures on long-lived assets	11,877	4,648	17,676	9,224
Goodwill	40,071	38,407	40,071	38,407	$ 38,508
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	809,798	1,030,816	1,723,682	2,049,777
Operating income	21,474	68,336	76,518	135,919
Expenditures on long-lived assets	11,877	4,648	17,676	9,224
Goodwill	40,071	38,407	40,071	38,407
Insurance
Segment Reporting Information [Line Items]
External revenue	13,716	14,224	27,398	28,263
Internal revenue	26,755	17,753	35,834	27,367
Investment income	835	1,283	2,002	2,421
Operating income	$ 10,707	$ 12,515	$ 9,668	$ 25,828