RESTRUCTURING, DIVESTITURES AND ASSETS HELD FOR SALE - Additional Information (Detail) - USD ($)	3 Months Ended				9 Months Ended		12 Months Ended		30 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2018
Restructuring Cost And Reserve [Line Items]
Non-cash impairment charges				$ 2,400,000
Restructuring charges	$ 100,000			13,900,000	$ 2,200,000
Employee termination				11,500,000
Payments for restructuring liability			$ 2,200,000
Proceeds from sale of business					25,200,000	$ 1,200,000
Non-cash impairments of goodwill							$ 65,000,000
Impairment of customer list intangibles					5,700,000		21,000,000
United Kingdom
Restructuring Cost And Reserve [Line Items]
Proceeds from sale of business		$ 8,200,000
Consideration for sale of business		11,500,000							$ 11,500,000
Consideration from business sale held in escrow		$ 3,300,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations | United Kingdom
Restructuring Cost And Reserve [Line Items]
Proceeds from sale of business						1,200,000
Assets and Liabilities Held for Sale, Not Discontinued Operations
Restructuring Cost And Reserve [Line Items]
Assets held for sale	0				0
Liabilities held for sale	0				0
Selling, General and Administrative Expenses | United Kingdom
Restructuring Cost And Reserve [Line Items]
Adjustment to estimate of exposure	400,000
Selling, General and Administrative Expenses | Disposal Group, Disposed of by Sale, Not Discontinued Operations | United Kingdom
Restructuring Cost And Reserve [Line Items]
Pre-tax loss from sale						5,600,000
Loss from sale, net of tax						$ 4,500,000
Selling, General and Administrative Expenses | Assets and Liabilities Held for Sale, Not Discontinued Operations | United Kingdom
Restructuring Cost And Reserve [Line Items]
Non-cash impairment charges					4,200,000		6,800,000	$ 3,800,000	$ 14,800,000
Domestic And Canada Regulated Waste And Compliance Services
Restructuring Cost And Reserve [Line Items]
Restructuring charges				5,500,000	1,700,000
Domestic And Canada Regulated Waste And Compliance Services | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Restructuring Cost And Reserve [Line Items]
Proceeds from sale of business	17,000,000
Pre-tax loss from sale	100,000
Loss from sale, net of tax	100,000
Domestic And Canada Regulated Waste And Compliance Services | Cost of Revenues
Restructuring Cost And Reserve [Line Items]
Non-cash impairment charges	6,800,000				6,800,000
Restructuring charges	1,000,000				1,000,000
Domestic And Canada Regulated Waste And Compliance Services | Selling, General and Administrative Expenses | Assets and Liabilities Held for Sale, Not Discontinued Operations
Restructuring Cost And Reserve [Line Items]
Non-cash impairment charges					6,900,000
Non-cash impairments of goodwill					5,800,000
Impairment of customer list intangibles					500,000
Reduction in fair value of assets					600,000
International Regulated Waste And Compliance Services
Restructuring Cost And Reserve [Line Items]
Restructuring charges				3,300,000	300,000
Non-cash impairments of goodwill							$ 65,000,000
All Other
Restructuring Cost And Reserve [Line Items]
Restructuring charges				$ 5,100,000	200,000
All Other | Selling, General and Administrative Expenses
Restructuring Cost And Reserve [Line Items]
Employee termination	1,100,000				1,100,000
Employee Termination Charges
Restructuring Cost And Reserve [Line Items]
Employee termination restructuring charges anticipated	20,000,000				20,000,000
Employee Termination Charges | Domestic And Canada Regulated Waste And Compliance Services
Restructuring Cost And Reserve [Line Items]
Employee termination restructuring charges anticipated	8,000,000				8,000,000
Employee Termination Charges | International Regulated Waste And Compliance Services
Restructuring Cost And Reserve [Line Items]
Employee termination restructuring charges anticipated	1,000,000				1,000,000
Employee Termination Charges | All Other
Restructuring Cost And Reserve [Line Items]
Employee termination restructuring charges anticipated	11,000,000				11,000,000
Lease Termination Fee | Domestic And Canada Regulated Waste And Compliance Services | Cost of Revenues
Restructuring Cost And Reserve [Line Items]
Restructuring charges	500,000				500,000
Non-cash Leasehold Improvements | Domestic And Canada Regulated Waste And Compliance Services | Cost of Revenues
Restructuring Cost And Reserve [Line Items]
Restructuring charges	$ 500,000				$ 500,000