Retirement Plan - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 30, 2013	Dec. 29, 2012
Compensation and Retirement Disclosure [Abstract]
Period during which company is required to purchase shares at fair value after distribution of shares from ESOP	15 months
Distributed shares subject to put option, fair value	$ 164,891	$ 126,647
ESOP, shares cost	2,371,640	2,146,316
Common stock related to ESOP	2,536,531	2,272,963
ESOP shares, fair value	$ 5,739,009	$ 5,418,856

Fair value of the shares allocated that are subject to a repurchase obligation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 93-6

-Paragraph 53

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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