STOCK-BASED COMPENSATION - Compensation Expense - Tabular Disclosure (Details) - USD ($) $ in Millions	12 Months Ended
May 31, 2020	May 26, 2019	May 27, 2018
Compensation expense
Stock-settled compensation expense	$ 22.8	$ 18.8	$ 13.5
Cash-settled RSUs	1.0	3.3	8.8
Total compensation expense	23.8	22.1	22.3
Income tax benefit	(4.6)	(4.4)	(5.6)
Total compensation expense, net of tax benefit	19.2	17.7	16.7
Stock-settled restricted stock units
Compensation expense
Stock-settled compensation expense	12.9	10.2	7.9
Performance shares
Compensation expense
Stock-settled compensation expense	9.8	8.3	4.4
Stock options
Compensation expense
Stock-settled compensation expense	$ 0.1	$ 0.3	$ 1.2

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

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

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