PENSION AND POSTRETIREMENT BENEFITS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Aug. 26, 2018	Aug. 27, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Multi-employer pension plans, withdrawal costs		$ 2.0
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Weighted average discount rate for service costs	4.21%
Weighted average discount rate for interest costs	3.83%
Employer contributions to pension and other postretirement plans	$ 4.2
Anticipated further contributions for the remainder of fiscal 2018	10.3
Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions to pension and other postretirement plans	2.6
Anticipated further contributions for the remainder of fiscal 2018	$ 13.6

Defined Benefit Plan, Interest Cost, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate

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Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of contributions expected to be received by defined benefit plan from employer in fiscal year. Excludes contributions paid by employer in current fiscal year.

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