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COMMITMENTS AND CONTINGENCIES - Additional Information (Detail) $ in Thousands |  |  | 1 Months Ended | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Apr. 28, 2017 USD ($) | Apr. 26, 2017 USD ($) | Apr. 30, 2011 USD ($) | May 31, 2009 USD ($) | Dec. 31, 2018 USD ($) | Sep. 30, 2017 USD ($) | Dec. 31, 2016 USD ($) | Sep. 30, 2016 USD ($) | Jan. 29, 2016 | Dec. 31, 2015 USD ($) | Dec. 20, 2000 a
Southbridge Landfill |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Environmental remediation liability |  |  |  |  |  | $ 6,179 | $ 0 | $ 0 |  | $ 0 |
Risk free interest percentage rate |  |  |  |  |  | 2.60% |  |  |  |  |
Potsdam Environmental Remediation Liability |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Amount of costs |  |  | $ 12,130 | $ 10,219 |  |  |  |  |  |  |
Environmental remediation liability |  |  |  |  |  | $ 5,845 | $ 5,866 | $ 4,966 |  | $ 5,221 |
Risk free interest percentage rate |  |  |  |  |  | 1.50% |  |  |  |  |
Scrap yard and solid waste transfer station (in acres) | a |  |  |  |  |  |  |  |  |  |  | 25
Remediation activities, participant share percentage |  |  |  |  |  |  |  |  | 15.00% |  |
21E Settlement and Water System Construction Funding Agreement | Bonds |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Bond period | 20 years |  |  |  |  |  |  |  |  |  |
Maximum | Southbridge Landfill | Scenario, Forecast |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Future cash payments |  |  |  |  | $ 3,069 |  |  |  |  |  |
Maximum | 21E Settlement and Water System Construction Funding Agreement | Bonds |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Amount of costs | $ 5,000 |  |  |  |  |  |  |  |  |  |
Notice of Intent to Sue under the Resource Conservation and Recovery Act | Maximum |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Amount of costs |  | $ 5,000 |  |  |  |  |  |  |  |  |
Notice of Intent to Sue under the Resource Conservation and Recovery Act | MADEP and Casella Waste System | Maximum |  |  |  |  |  |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |  |  |  |  |  |
Amount of costs |  | $ 10,000 |  |  |  |  |  |  |  |  |

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