LEASES - Lease Cost (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Operating lease cost:
Lease cost	$ 11.6	$ 33.4
Variable lease cost	3.1	8.8
Total operating lease cost	14.7	42.2
Short-term lease cost	1.3	3.5
Finance lease cost:
Amortization of right-of-use assets	0.7	2.2
Interest on lease liabilities	0.1	0.2
Total finance lease cost	0.8	2.4
Total lease cost	$ 16.8	$ 48.1