LEASES - Lease Cost (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Operating lease cost:
Lease cost	$ 10.4
Variable lease cost	2.9
Total operating lease cost	13.3
Short-term lease cost	1.1
Finance lease cost:
Amortization of right-of-use assets	0.8
Interest on lease liabilities	0.1
Total finance lease cost	0.9
Total lease cost	$ 15.3