BUSINESS COMBINATION - Summary of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Feb. 24, 2020	Jun. 30, 2020	Jun. 30, 2019
Business Acquisition [Line Items]
Acquisitions funded by deferred consideration		$ 1.7	$ 0.0
Coram Material Corp.
Business Acquisition [Line Items]
Accounts receivable	$ 2.0
Inventory	10.0
Other current assets	0.3
Property, plant and equipment	130.9
Total assets acquired	143.2
Current liabilities	0.1
Other long-term liabilities	0.2
Total liabilities assumed	0.3
Total consideration (fair value)	142.9
Consideration satisfied in cash	140.2
Acquisitions funded by deferred consideration	1.7
Working capital payable	1.6
Accounts payable	0.6
Maximum contingent consideration	$ 2.0
Contingent consideration payment period (years)	2 years