STOCK-BASED COMPENSATION - Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Feb. 23, 2020	Feb. 24, 2019	Feb. 23, 2020	Feb. 24, 2019
Compensation expense
Stock-settled compensation expense	$ 5.6	$ 4.5	$ 18.2	$ 13.7
Cash-settled RSUs			1.0	3.7
Total compensation expense	5.6	4.5	19.2	17.4
Income tax benefit	(1.1)	(0.9)	(3.6)	(3.4)
Total compensation expense, net of tax benefit	4.5	3.6	15.6	14.0
Stock-settled restricted stock units
Compensation expense
Stock-settled compensation expense	3.2	2.5	9.5	7.4
Performance shares
Compensation expense
Stock-settled compensation expense	$ 2.4	$ 2.0	8.6	6.1
Stock options
Compensation expense
Stock-settled compensation expense			$ 0.1	$ 0.2

Allocated Share-based Compensation Expense, Cash-settled Restricted Stock Units

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Allocated Share-based Compensation Expense, Stock-settled Compensation Expense

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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