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ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE - Summary of Changes to Accrued Capping, Closure and Post-Closure Liabilities (Detail) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning balance $ 82,533 $ 71,927
Obligations incurred 2,319 1,764
Revision in estimates 0 152
Accretion expense 3,676 3,204
Obligations settled (2,969) (1,650)
Ending balance $ 85,559 $ 75,397