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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Landfill Accounting (Detail)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
USD ($)
Agreement
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Property, Plant and Equipment [Line Items]      
Capitalized interest $ 295 $ 273 $ 62
Closure and post-closure costs incurrence period 30 years    
Estimate of inflation rate 1.70%    
Accretion expense $ 4,401 3,606  
Number of operation and management agreements entered into | Agreement 5    
Closure And Post Closure Costs      
Property, Plant and Equipment [Line Items]      
Accretion expense $ 4,401 3,606 $ 3,370
Surety bond 164,893 161,095  
Letters of credit $ 0 $ 0  
Minimum      
Property, Plant and Equipment [Line Items]      
Rate of asset retirement obligation 9.20%    
Maximum      
Property, Plant and Equipment [Line Items]      
Rate of asset retirement obligation 9.90%