Name:	unf_EstimatedImpactOfInflationPerYear
Namespace Prefix:	unf_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Number Of Insurance Companies

No definition available.

Name:	unf_NumberOfInsuranceCompanies
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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Number of Sites, Environmental

No definition available.

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

Tax assessment issued amount.

No definition available.

Name:	unf_TaxAssessmentIssuedAmount
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Tax assessment issued amount including surcharges fines and penalties.

No definition available.

Name:	unf_TaxAssessmentIssuedAmountIncludingSurchargesFinesAndPenalties
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Tax Assessment Issued Amount Net

No definition available.

Name:	unf_TaxAssessmentIssuedAmountNet
Namespace Prefix:	unf_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 954
-SubTopic 440
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478522/954-440-50-1

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

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483049/450-30-50-1

Name:	us-gaap_GainContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 25
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-25