LEASES - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Operating lease cost	$ 6.8	$ 19.8
Amortization of leased assets	3.0	8.6
Interest on lease liabilities	0.6	1.9
Total finance lease cost	3.6	10.5
Total	10.4	30.3
Short-term lease and variable lease costs	$ 1.9	$ 5.2