PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 3,782,092	$ 3,699,416
Less - accumulated depreciation and amortization	2,273,736	2,174,118
Total property, plant and equipment, net	1,508,356	1,525,298
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	150,257	139,776
Asset retirement costs (non-landfill)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	17,921	16,407
Landfill assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	200,545	191,687
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	524,397	509,804
Right-of-Use assets, finance leases	8,900	8,900
Camp equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	132,477	159,021
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	864,808	844,026
Right-of-Use assets, finance leases	65,900	47,200
Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,821,327	1,807,235
Right-of-Use assets, finance leases	9,300	9,300
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,838	7,082
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 63,522	$ 24,378