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Number of Insurance Companies

No definition available.

Name:	unf_NumberofInsuranceCompanies
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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
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Number of Sites, Environmental

No definition available.

Name:	unf_SiteContingencyEnvironmentalRemediationObligationsNumberofSites
Namespace Prefix:	unf_
Data Type:	xbrli:integerItemType
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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
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Tax Assessment Issued Amount Net

No definition available.

Name:	unf_TaxAssessmentIssuedAmountNet
Namespace Prefix:	unf_
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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10)
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 954
-SubTopic 440
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=6491277&loc=d3e6429-115629

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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.

No definition available.

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

Indicates (true false) whether lessee has option to extend operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918673-209980

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Data Type:	xbrli:booleanItemType
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Period Type:	duration

Indicates (true false) whether lessee has option to terminate operating lease.

Name:	us-gaap_LesseeOperatingLeaseExistenceOfOptionToTerminate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:booleanItemType
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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3536-108585

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

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Name:	us-gaap_IncomeTaxAuthorityNameAxis=us-gaap_MexicanTaxAuthorityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_TaxPeriodAxis=us-gaap_TaxYear2016Member
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Name:	srt_RangeAxis=srt_MinimumMember
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