Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Dec. 30, 2017
Segment Reporting Information [Line Items]
External revenue	$ 1,182,786	$ 870,434	$ 2,230,712	$ 1,651,342
Internal revenue	15,419	15,104	22,917	22,438
Investment income	891	608	1,752	1,022
Operating income	83,426	61,018	158,579	113,352
Expenditures on long-lived assets	307	1,650	4,121	6,628
Goodwill	38,704	31,134	38,704	31,134	$ 39,065
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	1,169,921	858,807	2,205,561	1,628,155
Operating income	78,998	50,398	146,298	94,512
Expenditures on long-lived assets	307	1,650	4,121	6,628
Goodwill	38,704	31,134	38,704	31,134
Insurance
Segment Reporting Information [Line Items]
External revenue	12,865	11,627	25,151	23,187
Internal revenue	15,419	15,104	22,917	22,438
Investment income	891	608	1,752	1,022
Operating income	$ 4,428	$ 10,620	$ 12,281	$ 18,840

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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