EMPLOYEE BENEFIT PLANS AND OTHER POST-RETIREMENT BENEFITS - Components of Net Periodic Benefit Cost and Other Comprehensive (Income) Loss - Tabular Disclosure (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	May 26, 2019	May 27, 2018
Pension Plans
EMPLOYEE BENEFIT PLANS AND OTHER POST-RETIREMENT BENEFITS
Net periodic benefit cost	$ 3.5	$ 5.9	$ 7.8
Total recognized in other comprehensive loss (income)	0.4	3.3	1.7
Total recognized in net periodic benefit cost and other comprehensive loss (income) (pre-tax)	3.9	9.2	9.5
Post-Retirement Plan
EMPLOYEE BENEFIT PLANS AND OTHER POST-RETIREMENT BENEFITS
Net periodic benefit cost	0.8	1.0	0.5
Total recognized in other comprehensive loss (income)	(1.6)	(0.7)	4.0
Total recognized in net periodic benefit cost and other comprehensive loss (income) (pre-tax)	$ (0.8)	$ 0.3	$ 4.5