REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of Revenues Disaggregated by Service, Primary Geographical Regions and Timing of Revenue Recognition (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation Of Revenue [Line Items]
Revenues	$ 854.9	$ 882.8	$ 2,633.2	$ 2,692.9
Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	606.7		1,810.6
Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	37.6		116.7
International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	95.7		316.4
International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	55.4		186.6
All Other
Disaggregation Of Revenue [Line Items]
Revenues	59.5	73.5	202.9	239.2
All Other | United States
Disaggregation Of Revenue [Line Items]
Revenues	59.5		202.9
Medical Waste and Compliance Solutions
Disaggregation Of Revenue [Line Items]
Revenues	394.6		1,222.8
Medical Waste and Compliance Solutions | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	283.4		860.5
Medical Waste and Compliance Solutions | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	9.7		29.4
Medical Waste and Compliance Solutions | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	58.9		189.2
Medical Waste and Compliance Solutions | International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	42.6		143.7
Hazardous Waste Solutions
Disaggregation Of Revenue [Line Items]
Revenues	82.0		235.0
Hazardous Waste Solutions | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	82.0		235.0
Manufacturing and Industrial Services
Disaggregation Of Revenue [Line Items]
Revenues	79.1	86.6	253.1	260.4
Manufacturing and Industrial Services | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	62.9		186.8
Manufacturing and Industrial Services | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	5.4		16.6
Manufacturing and Industrial Services | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	1.0		15.9
Manufacturing and Industrial Services | International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	9.8		33.8
Secure Information Destruction Services
Disaggregation Of Revenue [Line Items]
Revenues	227.6	$ 204.7	677.5	$ 621.2
Secure Information Destruction Services | Domestic and Canada RCS | United States
Disaggregation Of Revenue [Line Items]
Revenues	178.4		528.3
Secure Information Destruction Services | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	16.3		49.1
Secure Information Destruction Services | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	29.9		91.0
Secure Information Destruction Services | International RCS | Others
Disaggregation Of Revenue [Line Items]
Revenues	3.0		9.1
Communication Services
Disaggregation Of Revenue [Line Items]
Revenues	44.7		138.9
Communication Services | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	3.5		12.7
Communication Services | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	4.0		13.3
Communication Services | All Other | United States
Disaggregation Of Revenue [Line Items]
Revenues	37.2		112.9
Expert Solutions
Disaggregation Of Revenue [Line Items]
Revenues	26.9		105.9
Expert Solutions | Domestic and Canada RCS | Canada
Disaggregation Of Revenue [Line Items]
Revenues	2.7		8.9
Expert Solutions | International RCS | Europe
Disaggregation Of Revenue [Line Items]
Revenues	1.9		7.0
Expert Solutions | All Other | United States
Disaggregation Of Revenue [Line Items]
Revenues	$ 22.3		$ 90.0