PENSION AND POSTRETIREMENT BENEFITS - Schedule of Contributions for Plans That Are Not Individually Significant (Details) - USD ($) $ in Millions	12 Months Ended
May 31, 2020	May 26, 2019	May 27, 2018
Multiemployer Plans [Line Items]
Entity Tax Identification Number	47-0248710
Total Contributions	$ 6.5	$ 6.0	$ 6.5
Bakery and Confectionary Union and Industry International Pension Plan
Multiemployer Plans [Line Items]
Entity Tax Identification Number	52-6118572
PN	001
Pension Protection Act Zone Status		Red	Red
FIP / RP Status	Implemented
Total Contributions	$ 0.0	$ 0.1	$ 1.5
Surcharge Imposed	No
Central States, Southeast and Southwest Areas Pension Fund
Multiemployer Plans [Line Items]
Entity Tax Identification Number	36-6044243
PN	001
Pension Protection Act Zone Status		Red	Red
FIP / RP Status	Implemented
Total Contributions	$ 2.0	$ 1.8	$ 1.8
Surcharge Imposed	No
Expiration Dates of Collective Bargaining Agreements	May 31, 2021
Western Conference of Teamsters Pension Plan
Multiemployer Plans [Line Items]
Entity Tax Identification Number	91-6145047
PN	001
Pension Protection Act Zone Status		Green	Green
FIP / RP Status	NA
Total Contributions	$ 3.2	$ 3.2	$ 2.8
Surcharge Imposed	No
Expiration Dates of Collective Bargaining Agreements	Jun. 30, 2021
Other Plans
Multiemployer Plans [Line Items]
Total Contributions	$ 1.3	$ 0.9	$ 0.4

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12
-Subsection b-2

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Three digit plan number for a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

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- Definition

Indicate the multiemployer plan's certified zone status as currently required by the Pension Protection Act of 2006 or a subsequent amendment thereof. The zone status categories are red (critical status), orange (seriously endangered), yellow (endangered), and green (none of the above). The acceptable values are "red", "orange", "yellow", "green", "other", and "NA". A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

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- Definition

Expiration date of the collective bargaining arrangement requiring contributions to the multiemployer plan, in CCYY-MM-DD format. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (d)
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- Definition

Indicate whether a funding improvement plan or rehabilitation plan has been implemented or is pending for a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. The acceptable values are "no", "pending", "implemented", "other", and "NA".

+ References

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-Publisher FASB
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- Definition

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.

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No definition available.

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Amount of contributions made to multiemployer plan by all employers who participate in plan.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 7
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450678-114947

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- Definition

Indicate whether the employer paid a surcharge to the pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. The acceptable values are "no", "yes", and "NA".

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (f)(2)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

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