BUSINESS SEGMENT INFORMATION - Identifiable Assets by Segment (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Assets	$ 3,067.9	$ 3,031.8
Operating Segments | AWP
Segment Reporting Information [Line Items]
Assets	1,814.3	1,541.0
Operating Segments | MP
Segment Reporting Information [Line Items]
Assets	1,675.5	1,596.3
Corporate and Other / Eliminations
Segment Reporting Information [Line Items]
Assets	(428.9)	(111.8)
Discontinued Operations, Held-for-sale
Segment Reporting Information [Line Items]
Assets held for sale	$ 7.0	$ 6.3