Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 25, 2016	Jun. 27, 2015	Jun. 25, 2016	Jun. 27, 2015	Dec. 26, 2015
Segment Reporting Information [Line Items]
External revenue	$ 775,223	$ 868,383	$ 1,486,867	$ 1,630,763
Internal revenue	14,430	12,158	21,661	18,554
Investment income	363	339	743	693
Operating income	53,093	66,033	101,025	115,078
Expenditures on long-lived assets	8,127	600	8,955	3,050
Goodwill	31,134	31,134	31,134	31,134	$ 31,134
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	763,672	857,429	1,463,772	1,609,225
Operating income	46,176	57,383	85,801	101,113
Expenditures on long-lived assets	8,127	600	8,955	3,050
Goodwill	31,134	31,134	31,134	31,134
Insurance
Segment Reporting Information [Line Items]
External revenue	11,551	10,954	23,095	21,538
Internal revenue	14,430	12,158	21,661	18,554
Investment income	363	339	743	693
Operating income	$ 6,917	$ 8,650	$ 15,224	$ 13,965

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
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-Name Accounting Standards Codification
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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-Name Accounting Standards Codification
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Amount of operating interest income, including, but not limited to, amortization and accretion of premiums and discounts on securities.

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The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

+ References

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
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-URI http://asc.fasb.org/extlink&oid=16382449

Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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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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