Information Regarding Reportable Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 24, 2016	Sep. 26, 2015	Sep. 24, 2016	Sep. 26, 2015	Dec. 26, 2015
Segment Reporting Information [Line Items]
External revenue	$ 787,938	$ 841,726	$ 2,274,805	$ 2,472,489
Internal revenue	7,229	6,392	28,890	24,946
Investment income	357	350	1,100	1,043
Operating income	58,461	63,980	159,486	179,058
Expenditures on long-lived assets	8,878	748	17,833	3,798
Goodwill	31,134	31,134	31,134	31,134	$ 31,134
Transportation Logistics
Segment Reporting Information [Line Items]
External revenue	776,397	830,397	2,240,169	2,439,622
Operating income	47,541	53,767	133,342	154,880
Expenditures on long-lived assets	8,878	748	17,833	3,798
Goodwill	31,134	31,134	31,134	31,134
Insurance
Segment Reporting Information [Line Items]
External revenue	11,541	11,329	34,636	32,867
Internal revenue	7,229	6,392	28,890	24,946
Investment income	357	350	1,100	1,043
Operating income	$ 10,920	$ 10,213	$ 26,144	$ 24,178

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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-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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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
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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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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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