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FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS - Changes to Accrued Capping, Closure and Post-Closure Liabilities (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Beginning balance $ 41,041 $ 39,829
Obligations incurred 2,441 1,798
Revisions in estimates (2,052) (2,030)
Accretion expense 3,606 3,370
Obligations settled (829) (1,926)
Ending balance $ 44,207 $ 41,041