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ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE | 3 Months Ended
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Mar. 31, 2018
Asset Retirement Obligation Disclosure [Abstract] |
ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE | ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE Accrued final capping, closure and post-closure costs include the current and non-current portion of costs associated with obligations for final capping, closure and post-closure of our landfills. We estimate our future final capping, closure and post-closure costs in order to determine the final capping, closure and post-closure expense per ton of waste placed into each landfill. The anticipated time frame for paying these costs varies based on the remaining useful life of each landfill as well as the duration of the post-closure monitoring period. A summary of the changes to accrued final capping, closure and post-closure liabilities follows:
| Three Months Ended March 31,
| 2018 |  | 2017
Beginning balance | $ | 62,290 |  |  | $ | 44,207 |
Obligations incurred | 798 |  |  | 556 |
Revision in estimates (1) | 1,492 |  |  | — |
Accretion expense | 1,383 |  |  | 965 |
Obligations settled (2) | (297 | ) |  | (126 | )
Ending balance | $ | 65,666 |  |  | $ | 45,602 |
(1) | Relates to changes in estimates and assumptions associated with anticipated costs of future final capping, closure and post-closure activities at the Town of Southbridge, Massachusetts Landfill. See Note 8, Commitments and Contingencies and Note 11, Other Items and Charges for disclosure regarding the matter.
(2) | Includes amounts that are being processed through accounts payable as a part of our disbursements cycle.

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- References No definition available. + Details
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- Definition The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -URI http://asc.fasb.org/subtopic&trid=2175671 + Details
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