Information Regarding Reportable Business Segments (Detail) - USD ($)	12 Months Ended
	Dec. 26, 2020	Dec. 28, 2019	Dec. 29, 2018
Segment Reporting Information [Line Items]
External revenue	$ 4,132,981,000	$ 4,084,577,000	$ 4,615,144,000
Internal revenue	54,003,000	46,587,000	37,872,000
Investment income	3,399,000	5,041,000	3,816,000
Interest and debt expense	3,953,000	3,141,000	3,354,000
Depreciation and amortization	45,855,000	44,468,000	43,570,000
Operating income	252,950,000	298,904,000	331,735,000
Expenditures on long-lived assets	30,626,000	19,416,000	9,747,000
Goodwill	40,949,000	38,508,000	38,232,000
Finance lease additions	31,633,000	29,054,000	46,595,000
Total assets	1,653,799,000	1,427,711,000	1,380,564,000
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	4,076,519,000	4,028,336,000	4,562,796,000
Interest and debt expense	3,953,000	3,141,000	3,354,000
Depreciation and amortization	45,855,000	44,468,000	43,570,000
Operating income	221,210,000	258,742,000	303,426,000
Expenditures on long-lived assets	30,626,000	19,416,000	9,747,000
Goodwill	40,949,000	38,508,000	38,232,000
Finance lease additions	31,633,000	29,054,000	46,595,000
Total assets	1,301,991,000	1,168,944,000	1,175,040,000
Insurance
Segment Reporting Information [Line Items]
External revenue	56,462,000	56,241,000	52,348,000
Internal revenue	54,003,000	46,587,000	37,872,000
Investment income	3,399,000	5,041,000	3,816,000
Operating income	31,740,000	40,162,000	28,309,000
Total assets	$ 351,808,000	$ 258,767,000	$ 205,524,000