STOCK-BASED COMPENSATION - Unrecognized Compensation Expense, Net of Estimated Forfeitures (Details) $ in Millions	9 Months Ended
	Feb. 23, 2020 USD ($)
Unrecognized compensation expense, net of estimated forfeitures
Unrecognized Compensation Expense	$ 32.7
Remaining Weighted Average Recognition Period (in years)	1 year 10 months 24 days
Stock-settled restricted stock units
Unrecognized compensation expense, net of estimated forfeitures
Unrecognized Compensation Expense	$ 19.5
Remaining Weighted Average Recognition Period (in years)	1 year 10 months 24 days
Performance shares
Unrecognized compensation expense, net of estimated forfeitures
Unrecognized Compensation Expense	$ 13.2
Remaining Weighted Average Recognition Period (in years)	1 year 9 months 18 days