GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of Purchased Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	$ 190.6	$ 190.6
Accumulated Amortization	(104.7)	(99.4)
Total	$ 85.9	$ 91.2
Weighted Average Remaining Life (In Years)	9 years 6 months	9 years 4 months 24 days
Total purchased intangible assets, Gross	$ 191.8	$ 191.8
Total purchased intangible assets, Accumulated Amortization	(104.7)	(99.4)
Total purchased intangible assets, Net	87.1	92.4
Land rights
Acquired Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	1.2	1.2
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	108.5	108.5
Accumulated Amortization	(63.5)	(59.7)
Total	$ 45.0	$ 48.8
Weighted Average Remaining Life (In Years)	3 years 8 months 12 days	3 years 10 months 24 days
Total purchased intangible assets, Accumulated Amortization	$ (63.5)	$ (59.7)
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	44.5	44.5
Accumulated Amortization	(14.1)	(13.6)
Total	$ 30.4	$ 30.9
Weighted Average Remaining Life (In Years)	18 years 10 months 24 days	19 years 1 month 6 days
Total purchased intangible assets, Accumulated Amortization	$ (14.1)	$ (13.6)
Non-competes
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	18.3	18.3
Accumulated Amortization	(15.8)	(15.3)
Total	$ 2.5	$ 3.0
Weighted Average Remaining Life (In Years)	2 years 3 months 18 days	2 years 4 months 24 days
Total purchased intangible assets, Accumulated Amortization	$ (15.8)	$ (15.3)
Leasehold interests
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	12.5	12.5
Accumulated Amortization	(7.2)	(6.7)
Total	$ 5.3	$ 5.8
Weighted Average Remaining Life (In Years)	5 years 3 months 18 days	5 years 4 months 24 days
Total purchased intangible assets, Accumulated Amortization	$ (7.2)	$ (6.7)
Favorable contracts
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	4.0	4.0
Accumulated Amortization	(3.9)	(3.9)
Total	$ 0.1	$ 0.1
Weighted Average Remaining Life (In Years)	8 months 12 days	10 months 24 days
Total purchased intangible assets, Accumulated Amortization	$ (3.9)	$ (3.9)
Environmental credits
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	2.8	2.8
Accumulated Amortization	(0.2)	(0.2)
Total	$ 2.6	$ 2.6
Weighted Average Remaining Life (In Years)	15 years 9 months 18 days	16 years
Total purchased intangible assets, Accumulated Amortization	$ (0.2)	$ (0.2)