CLOSURE AND POST-CLOSURE LIABILITIES - Changes in Post-Closure Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) landfill_site
Changes to post-closure liabilities
Balance at the beginning of the period	$ 87,926	$ 75,651
Liabilities assumed in acquisitions	1,446	265
New asset retirement obligations	2,443	2,101
Accretion	7,357	6,653
Changes in estimates recorded to consolidated statement of operations	2,683	6,568
Changes in estimates recorded to consolidated balance sheet	3,712	682
Expenditures	(6,602)	(4,198)
Currency translation and other	138	204
Balance at the end of the period	99,103	$ 87,926
Number of landfill sites closed during period | landfill_site		2
Increase in facility closure costs	2,300	$ 6,800
Landfill Retirement Liability
Changes to post-closure liabilities
Balance at the beginning of the period	48,412	39,401
Liabilities assumed in acquisitions	0	0
New asset retirement obligations	2,443	2,101
Accretion	3,655	3,254
Changes in estimates recorded to consolidated statement of operations	2,287	6,465
Changes in estimates recorded to consolidated balance sheet	2,297	481
Expenditures	(5,818)	(3,445)
Currency translation and other	149	155
Balance at the end of the period	53,425	48,412
Non-Landfill Retirement Liability
Changes to post-closure liabilities
Balance at the beginning of the period	39,514	36,250
Liabilities assumed in acquisitions	1,446	265
New asset retirement obligations	0	0
Accretion	3,702	3,399
Changes in estimates recorded to consolidated statement of operations	396	103
Changes in estimates recorded to consolidated balance sheet	1,415	201
Expenditures	(784)	(753)
Currency translation and other	(11)	49
Balance at the end of the period	$ 45,678	$ 39,514