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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Landfill Accounting (Detail)
$ in Thousands
 12 Months Ended
Dec. 31, 2018
USD ($)
Agreement
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Property, Plant and Equipment [Line Items]      
Capitalized interest $ 140 $ 295 $ 273
Closure and post-closure costs incurrence period 30 years    
Estimate of inflation rate (as a percent) 1.50%    
Accretion expense $ 5,556 4,401  
Number of operation and management agreements entered into | Agreement 4    
Closure And Post Closure Costs      
Property, Plant and Equipment [Line Items]      
Accretion expense $ 5,556 4,401 $ 3,606
Surety bond 201,177 164,893  
Letters of credit $ 0 $ 0  
Minimum      
Property, Plant and Equipment [Line Items]      
Rate of asset retirement obligation (as a percent) 8.70%    
Maximum      
Property, Plant and Equipment [Line Items]      
Rate of asset retirement obligation (as a percent) 9.80%