Name:	unf_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsMaximumNumberOfSharesEligibleToBeEarned
Namespace Prefix:	unf_
Data Type:	xbrli:sharesItemType
Balance Type:	na
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The threshold for number of Shares eligible to be earned during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

No definition available.

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The target number of shares eligible to be earned during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

No definition available.

Name:	unf_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetNumberOfSharesEligibleToBeEarned
Namespace Prefix:	unf_
Data Type:	xbrli:sharesItemType
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Unrecognized cost of unvested share-based compensation awards.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Period Type:	instant

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Data Type:	xbrli:durationItemType
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Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
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Period Type:	duration

Price of a single share of a number of saleable stocks of a company.

No definition available.

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Data Type:	num:perShareItemType
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Period Type:	instant

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Data Type:	na
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Namespace Prefix:
Data Type:	na
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Namespace Prefix:
Data Type:	na
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