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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
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning balance $ 82,533 $ 71,927
Obligations incurred 1,038 898
Accretion expense 1,811 1,622
Obligations settled (357) (1,097)
Ending balance $ 85,025 $ 73,350