EMPLOYEE BENEFIT PLANS AND OTHER POST-RETIREMENT BENEFITS - Changes in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	May 26, 2019
Pension Plans
Change in Plan Assets
Fair value of plan assets at beginning of year	$ 17.1	$ 17.3
Actual return on plan assets	6.6	(0.3)
Company contributions	3.8	0.4
Benefits paid	(0.3)	(0.3)
Fair value of plan assets at end of year	27.2	17.1
Post-Retirement Plan
Change in Plan Assets
Company contributions	0.1	0.1
Participants contributions	0.2	0.2
Benefits paid	$ (0.3)	$ (0.3)