Funded Status of Retiree Medical Plan (Detail) - Retiree Medical Plan - USD ($) $ in Thousands	Dec. 25, 2021	Dec. 26, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit obligation at end of fiscal year	$ 1,040	$ 1,077
Unfunded Status	$ 1,040	$ 1,077

Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=123453770&loc=d3e1703-114919

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant