FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS

12 Months Ended

Dec. 31, 2019

Asset Retirement Obligation Disclosure [Abstract]

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTS

FINAL CAPPING, CLOSURE AND POST-CLOSURE COSTSAccrued 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 as further described in Note 3, Summary of Significant Accounting Policies. 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.

The changes to accrued final capping, closure and post-closure liabilities are as follows:

	Fiscal Year Ended December 31,
	2019		2018
Beginning balance	$	73,075	$	62,290
Obligations incurred	2,549		3,713
Revisions in estimates (1)	(1,538)		5,095
Accretion expense	6,227		5,556
Obligations settled (2)	(8,386)		(3,579)
Ending balance	$	71,927	$	73,075

(1)Relates to changes in estimates and assumptions concerning anticipated waste flow, cost and timing of future final capping, closure and post-closure activities at certain landfills, including the Subtitle D landfill in Southbridge, Massachusetts ("Southbridge Landfill"), as well as changes to expansion airspace at other landfills. See Note 17, Other Items and Charges for disclosure regarding Southbridge Landfill.

(2)Includes amounts paid and amounts that are being processed through accounts payable as a part of our disbursement cycle.