LEASES - Supplemental Cash Flow Information (Details) $ in Millions	12 Months Ended
	May 31, 2020 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Cash used for operating activities	$ 26.8
Cash paid for amounts included in the measurement of lease liabilities:
Cash used for financing activities	2.6
Noncash investing and financing activities:
Asset obtained in exchange for new operating lease obligations	41.4
Assets obtained in exchange for new finance lease obligations	$ 2.2