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SEGMENT INFORMATION - Narrative (Details) $ in Millions	7 Months Ended	12 Months Ended
SEGMENT INFORMATION - Narrative (Details) $ in Millions	Dec. 31, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018	Dec. 31, 2018 segment	Dec. 31, 2018 reporting_units	Dec. 31, 2017 USD ($)	May 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments				3	3
Sales Revenue, Net \| Geographic Concentration Risk \| United States
Segment Reporting Information [Line Items]
Percentage of total consolidated revenues from external customers	67.00%		67.00%			66.00%	61.00%
Sales Revenue, Net \| Geographic Concentration Risk \| United Kingdom
Segment Reporting Information [Line Items]
Percentage of total consolidated revenues from external customers	10.00%		9.00%			11.00%	10.00%
Sales Revenue, Net \| Geographic Concentration Risk \| Canada
Segment Reporting Information [Line Items]
Percentage of total consolidated revenues from external customers							10.00%
Heartland
Segment Reporting Information [Line Items]
Acquisition and integration expenses	$ 91.6	$ 56.1				$ 94.6	$ 51.3