REVENUES 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								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Revenues	$ 799.9	$ 833.1	$ 845.8	$ 830.1	$ 852.7	$ 854.9	$ 883.3	$ 895.0	$ 3,308.9	$ 3,485.9	$ 3,580.7
United States
Disaggregation Of Revenue [Line Items]
Revenues									2,578.0	2,673.6	2,716.9
Medical Waste and Compliance Services
Disaggregation Of Revenue [Line Items]
Revenues									1,571.5	1,618.5
Hazardous Waste Services
Disaggregation Of Revenue [Line Items]
Revenues									321.3	314.1
Regulated Waste and Compliance Services
Disaggregation Of Revenue [Line Items]
Revenues									1,892.8	1,932.6	2,023.6
Secure Information Destruction Services
Disaggregation Of Revenue [Line Items]
Revenues									901.9	911.0	823.4
Manufacturing and Industrial Services
Disaggregation Of Revenue [Line Items]
Revenues									295.0	329.2	351.1
Communication Services
Disaggregation Of Revenue [Line Items]
Revenues									133.8	184.1
Expert Solutions
Disaggregation Of Revenue [Line Items]
Revenues									85.4	129.0
Communication Related Services
Disaggregation Of Revenue [Line Items]
Revenues									219.2	313.1
North America RWCS
Disaggregation Of Revenue [Line Items]
Revenues									2,544.2	2,574.1	2,551.9
North America RWCS | United States
Disaggregation Of Revenue [Line Items]
Revenues									2,392.6	2,416.9
North America RWCS | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									151.6	157.2
North America RWCS | Medical Waste and Compliance Services | United States
Disaggregation Of Revenue [Line Items]
Revenues									1,127.9	1,142.4
North America RWCS | Medical Waste and Compliance Services | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									41.8	39.6
North America RWCS | Hazardous Waste Services | United States
Disaggregation Of Revenue [Line Items]
Revenues									321.3	314.1
North America RWCS | Regulated Waste and Compliance Services | United States
Disaggregation Of Revenue [Line Items]
Revenues									1,449.2	1,456.5
North America RWCS | Regulated Waste and Compliance Services | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									41.8	39.6
North America RWCS | Secure Information Destruction Services | United States
Disaggregation Of Revenue [Line Items]
Revenues									705.1	712.6
North America RWCS | Secure Information Destruction Services | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									64.4	65.7
North America RWCS | Manufacturing and Industrial Services | United States
Disaggregation Of Revenue [Line Items]
Revenues									238.3	247.8
North America RWCS | Manufacturing and Industrial Services | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									23.3	22.6
North America RWCS | Communication Services | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									12.1	17.3
North America RWCS | Expert Solutions | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									10.0	12.0
North America RWCS | Communication Related Services | CANADA
Disaggregation Of Revenue [Line Items]
Revenues									22.1	29.3
International RWCS
Disaggregation Of Revenue [Line Items]
Revenues									579.3	655.1
International RWCS | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									448.5	481.8
International RWCS | Others
Disaggregation Of Revenue [Line Items]
Revenues									130.8	173.3
International RWCS | Medical Waste and Compliance Services | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									300.7	305.1
International RWCS | Medical Waste and Compliance Services | Others
Disaggregation Of Revenue [Line Items]
Revenues									101.1	131.4
International RWCS | Regulated Waste and Compliance Services | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									300.7	305.1
International RWCS | Regulated Waste and Compliance Services | Others
Disaggregation Of Revenue [Line Items]
Revenues									101.1	131.4
International RWCS | Secure Information Destruction Services | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									132.4	132.7
International RWCS | Manufacturing and Industrial Services | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									3.7	16.9
International RWCS | Manufacturing and Industrial Services | Others
Disaggregation Of Revenue [Line Items]
Revenues									29.7	41.9
International RWCS | Communication Services | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									4.4	18.4
International RWCS | Expert Solutions | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									7.3	8.7
International RWCS | Communication Related Services | EMEA
Disaggregation Of Revenue [Line Items]
Revenues									11.7	27.1
All Other
Disaggregation Of Revenue [Line Items]
Revenues									185.4	256.7	$ 321.2
All Other | United States
Disaggregation Of Revenue [Line Items]
Revenues									185.4	256.7
All Other | Communication Services | United States
Disaggregation Of Revenue [Line Items]
Revenues									117.3	148.4
All Other | Expert Solutions | United States
Disaggregation Of Revenue [Line Items]
Revenues									68.1	108.3
All Other | Communication Related Services | United States
Disaggregation Of Revenue [Line Items]
Revenues									$ 185.4	$ 256.7