SHARE-BASED PAYMENTS - Unrecognized compensation expense, net of estimated forfeitures (Details) $ in Millions	9 Months Ended
	Feb. 26, 2017 USD ($)
Unrecognized compensation expense, net of estimated forfeitures
Unrecognized Compensation Expense	$ 18.8
Remaining Weighted Average Recognition Period (in years)	2 years
Stock options
Unrecognized compensation expense, net of estimated forfeitures
Unrecognized Compensation Expense	$ 1.4
Remaining Weighted Average Recognition Period (in years)	1 year 7 months 6 days
Cash-settled restricted stock units
Unrecognized compensation expense, net of estimated forfeitures
Unrecognized Compensation Expense	$ 7.9
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	$ 8.5
Remaining Weighted Average Recognition Period (in years)	2 years 1 month 6 days
Performance Units
Unrecognized compensation expense, net of estimated forfeitures
Unrecognized Compensation Expense	$ 1.0
Remaining Weighted Average Recognition Period (in years)	1 year 9 months 18 days