BUSINESS DESCRIPTION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Self-Insurance Accruals, Right of Use Asset, Lease Liabilities and Rent Expense, Shipping and Handling Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Self-Insurance Accruals
(Increase) decrease in self-insurance expense due to change in estimates related to prior year open policy periods	$ 3.1	$ (1.3)	$ 1.2
Self-insurance accruals, current	8.5	10.1
Self-insurance accruals, noncurrent	20.3	23.6
Shipping and Handling
Shipping and Handling Costs:
Costs of goods sold	$ 8.6	$ 7.7	$ 6.1