GOODWILL AND INTANGIBLE ASSETS - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Asset Cost	$ 830.3	$ 807.0
Accumulated Amortization	339.6	254.6
Net Book Value	490.7	552.4
Customer lists
Finite-Lived Intangible Assets [Line Items]
Gross Asset Cost	781.1	757.7
Accumulated Amortization	313.7	233.7
Net Book Value	467.4	524.0
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Gross Asset Cost	4.7	4.7
Accumulated Amortization	4.6	4.6
Net Book Value	$ 0.1	0.1
Intellectual property
Finite-Lived Intangible Assets [Line Items]
Amortization period	10 years
Gross Asset Cost	$ 38.3	38.6
Accumulated Amortization	15.4	11.3
Net Book Value	22.9	27.3
Tradename
Finite-Lived Intangible Assets [Line Items]
Gross Asset Cost	6.2	6.0
Accumulated Amortization	5.9	5.0
Net Book Value	$ 0.3	$ 1.0
Minimum
Finite-Lived Intangible Assets [Line Items]
Amortization period	3 years
Minimum | Customer lists
Finite-Lived Intangible Assets [Line Items]
Amortization period	3 years
Minimum | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Amortization period	3 years
Minimum | Tradename
Finite-Lived Intangible Assets [Line Items]
Amortization period	1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Amortization period	20 years
Maximum | Customer lists
Finite-Lived Intangible Assets [Line Items]
Amortization period	20 years
Maximum | Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Amortization period	5 years
Maximum | Tradename
Finite-Lived Intangible Assets [Line Items]
Amortization period	3 years