REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of Revenues Disaggregated by Service, Primary Geographical Regions and Timing of Revenue Recognition (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Disaggregation Of Revenue [Line Items]
Revenues	$ 895.0
Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	599.4
Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	39.1
International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	112.5
International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	67.8
Other | United States
Disaggregation Of Revenue [Line Items]
Revenues	76.2
Medical Waste and Compliance Solutions
Disaggregation Of Revenue [Line Items]
Revenues	419.9
Medical Waste and Compliance Solutions | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	292.8
Medical Waste and Compliance Solutions | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	9.8
Medical Waste and Compliance Solutions | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	65.3
Medical Waste and Compliance Solutions | International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	52.0
Hazardous Waste Solutions
Disaggregation Of Revenue [Line Items]
Revenues	77.5
Hazardous Waste Solutions | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	77.5
Manufacturing and Industrial Services
Disaggregation Of Revenue [Line Items]
Revenues	85.8
Manufacturing and Industrial Services | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	58.8
Manufacturing and Industrial Services | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	5.5
Manufacturing and Industrial Services | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	8.7
Manufacturing and Industrial Services | International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	12.8
Secure Information Destruction Services
Disaggregation Of Revenue [Line Items]
Revenues	219.9
Secure Information Destruction Services | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	170.3
Secure Information Destruction Services | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	16.2
Secure Information Destruction Services | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	30.4
Secure Information Destruction Services | International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	3.0
Communication Services
Disaggregation Of Revenue [Line Items]
Revenues	49.5
Communication Services | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	4.5
Communication Services | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	5.3
Communication Services | Other | United States
Disaggregation Of Revenue [Line Items]
Revenues	39.7
Expert Solutions
Disaggregation Of Revenue [Line Items]
Revenues	42.4
Expert Solutions | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	3.1
Expert Solutions | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	2.8
Expert Solutions | Other | United States
Disaggregation Of Revenue [Line Items]
Revenues	$ 36.5