ACCRUED FINAL CAPPING, CLOSURE AND POST CLOSURE (Tables)

3 Months Ended

Mar. 31, 2018

Asset Retirement Obligation Disclosure [Abstract]

Summary of Changes to Accrued Capping, Closure and Post-Closure Liabilities

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.