Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2021	Mar. 28, 2020	Dec. 26, 2020
Segment Reporting Information [Line Items]
External revenue	$ 1,287,534	$ 927,566
Internal revenue	9,534	9,079
Investment income	684	1,167
Operating income	103,268	54,005
Expenditures on long-lived assets	4,076	5,799
Goodwill	40,732	37,182	$ 40,949
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	1,270,499	913,884
Operating income	89,732	55,044
Expenditures on long-lived assets	4,076	5,799
Goodwill	40,732	37,182
Insurance
Segment Reporting Information [Line Items]
External revenue	17,035	13,682
Internal revenue	9,534	9,079
Investment income	684	1,167
Operating income	$ 13,536	$ (1,039)