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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
9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning balance $ 82,533 $ 71,927
Obligations incurred 3,638 2,820
Revision in estimates 0 152
Accretion expense 5,496 4,826
Obligations settled (5,394) (2,706)
Ending balance $ 86,273 $ 77,019