LEASES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	May 26, 2019	May 27, 2018
Schedule Of Lease [Line Items]
Lessee, operating lease, existence of option to extend	true
Lessee, operating lease, existence of option to terminate	true
Lessee, finance lease, existence of option to extend	true
Lessee, finance lease, existence of option to terminate	true
Operating lease cost	$ 63.7
Lessee, lease payment not yet commenced	2.0
Rent expense under all operating leases		$ 83.5	$ 62.5
Non-cash issuances of capital and financing lease obligations		$ 23.5	$ 1.3
Pinnacle Integration Restructuring Plan
Schedule Of Lease [Line Items]
Operating lease cost	9.9
Pinnacle Integration Restructuring Plan | Selling, general and administrative expenses
Schedule Of Lease [Line Items]
Impairments of ROU assets	$ 2.9