Name:	unf_EstimatedImpactOfInflationPerYear
Namespace Prefix:	unf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the amount the company's insurance is paying to the creditors as part of the chapter 11 settlement.

No definition available.

Name:	unf_InsurerPaymentsToCreditorsInChapter11Settlement
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

Name:	unf_Note11CommitmentsandContingenciesDetailsLineItems
Namespace Prefix:	unf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

This element represents the number of sites related to former operations that are subject to remediation of certain hazardous or toxic substances.

No definition available.

Name:	unf_NumberOfSitesRelatedToFormerOperationsWithEnvironmentalIssues
Namespace Prefix:	unf_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

This element represent the risk-free rate of interest used to discount the remediation costs. A risk-free rate represents the interest that an investor would expect from an absolutely risk-free investment over a given period of time.

No definition available.

Name:	unf_RiskFreeRatesOfInterestUsedToDiscountRemediationCosts
Namespace Prefix:	unf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Increase (decrease) in the accrual for environmental loss contingencies during the reporting period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.Y.Q2)

-URI http://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751

Name:	us-gaap_AccrualForEnvironmentalLossContingenciesPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

The designation of funds furnished by a borrower to a lender to assure future payments of the borrower's real estate taxes and insurance obligations with respect to a mortgaged property. Escrow deposits may be made for a variety of other purposes such as earnest money and contingent payments. This element excludes replacement reserves which are an escrow separately provided for within the US GAAP taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

No definition available.

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

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

Cash received for the settlement of litigation during the current period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585