FAIR VALUE MEASUREMENTS - Fair Value Hierarchy (Details) - Recurring - USD ($) $ in Millions	Feb. 28, 2021	May 31, 2020
Assets:
Deferred compensation assets		$ 0.1
Derivative assets	$ 7.3
Total assets	7.3	0.1
Liabilities:
Derivative liabilities		4.7
Deferred compensation liabilities	22.7	18.0
Total liabilities	22.7	22.7
Level 1
Assets:
Deferred compensation assets		0.1
Total assets		0.1
Level 2
Assets:
Derivative assets	7.3
Total assets	7.3
Liabilities:
Derivative liabilities		4.7
Deferred compensation liabilities	22.7	18.0
Total liabilities	$ 22.7	$ 22.7