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
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenues	$ 668.0	$ 785.0
Regulated Waste and Compliance Services
Disaggregation of Revenue [Line Items]
Revenues	473.6	566.9
Secure Information Destruction Services
Disaggregation of Revenue [Line Items]
Revenues	194.4	218.1
North America
Disaggregation of Revenue [Line Items]
Revenues	533.7	654.6
North America | Regulated Waste and Compliance Services
Disaggregation of Revenue [Line Items]
Revenues	366.8	468.6
North America | Secure Information Destruction Services
Disaggregation of Revenue [Line Items]
Revenues	166.9	186.0
International
Disaggregation of Revenue [Line Items]
Revenues	134.3	130.4
International | Regulated Waste and Compliance Services
Disaggregation of Revenue [Line Items]
Revenues	106.8	98.3
International | Secure Information Destruction Services
Disaggregation of Revenue [Line Items]
Revenues	$ 27.5	$ 32.1