Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Apr. 01, 2017	Dec. 30, 2017
Segment Reporting Information [Line Items]
External revenue	$ 1,047,926	$ 780,908
Internal revenue	7,498	7,334
Investment income	861	414
Operating income	75,153	52,334
Expenditures on long-lived assets	3,814	4,978
Goodwill	39,363	31,134	$ 39,065
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	1,035,640	769,348
Operating income	67,300	44,114
Expenditures on long-lived assets	3,814	4,978
Goodwill	39,363	31,134
Insurance
Segment Reporting Information [Line Items]
External revenue	12,286	11,560
Internal revenue	7,498	7,334
Investment income	861	414
Operating income	$ 7,853	$ 8,220

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (c)
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
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-Section S99
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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