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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, 2019
Mar. 31, 2018
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning balance $ 73,075 $ 62,290
Obligations incurred 543 798
Revision in estimates 0 1,492
Accretion expense 1,607 1,383
Obligations settled (1,556) (297)
Ending balance $ 73,669 $ 65,666