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A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

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Entity Information (USD $)	9 Months Ended
Entity Information (USD $)	May 28, 2011	Jul. 01, 2011	Feb. 26, 2011
Entity Information [Line Items]
Entity Registrant Name	UniFirst Corporation
Entity Central Index Key	0000717954
Current Fiscal Year End Date	--08-27
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 801,785,035
Entity Common Stock, shares outstanding		19,868,648
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q3
Class A
Entity Information [Line Items]
Entity Common Stock, shares outstanding		14,966,079
Class B
Entity Information [Line Items]
Entity Common Stock, shares outstanding		4,902,569