CLOSURE AND POST-CLOSURE LIABILITIES (Changes in Post-Closure Liabilities) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2020 USD ($) landfill_site	Dec. 31, 2019 USD ($)
Changes to post-closure liabilities
Balance at the beginning of the period	$ 75,651	$ 69,931
Liabilities assumed in acquisitions	265	220
New asset retirement obligations	2,101	2,705
Accretion	6,653	5,601
Changes in estimates recorded to consolidated statement of operations	6,568	2,685
Changes in estimates recorded to consolidated balance sheet	682	3,865
Expenditures	(4,198)	(9,839)
Currency translation and other	204	483
Balance at the end of the period	$ 87,926	75,651
Number of landfill sites closed during period \| landfill_site	2
Environmental remediation expense	$ 6,800
Increase in facility closure costs		2,300
Landfill Retirement Liability
Changes to post-closure liabilities
Balance at the beginning of the period	39,401	37,809
Liabilities assumed in acquisitions	0	0
New asset retirement obligations	2,101	2,705
Accretion	3,254	2,772
Changes in estimates recorded to consolidated statement of operations	6,465	248
Changes in estimates recorded to consolidated balance sheet	481	3,303
Expenditures	(3,445)	(7,718)
Currency translation and other	155	282
Balance at the end of the period	48,412	39,401
Non-Landfill Retirement Liability
Changes to post-closure liabilities
Balance at the beginning of the period	36,250	32,122
Liabilities assumed in acquisitions	265	220
New asset retirement obligations	0	0
Accretion	3,399	2,829
Changes in estimates recorded to consolidated statement of operations	103	2,437
Changes in estimates recorded to consolidated balance sheet	201	562
Expenditures	(753)	(2,121)
Currency translation and other	49	201
Balance at the end of the period	$ 39,514	$ 36,250

Asset Retirement Obligation, Adjustment Related to Disposition of Business

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- Definition

Represents the amount of change in the asset retirement obligation, during the current period for other changes in estimates recorded in the balance sheet.

+ References

No definition available.

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The amount of change in the asset retirement obligation, during the current period, for changes in estimates recorded in the statement of income.

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No definition available.

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Asset Retirement Obligation, Changes Recorded In Statement Of Income, Related To Increased Facility Closure Costs

+ References

No definition available.

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- Definition

Asset Retirement Obligation, Liabilities Assumed in Acquisition

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No definition available.

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Number Of Commercial Landfill Sites Closed During Period

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No definition available.

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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement 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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
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Amount of foreign currency translation gain (loss) which decreases (increases) asset retirement obligations.

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Amount of asset retirement obligations incurred during the period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
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Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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- Definition

The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109237650&loc=d3e13064-110858

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 30
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13296-110859

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