PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 3,644,204	$ 3,593,814
Less - accumulated depreciation and amortization	2,104,871	2,005,663
Total property, plant and equipment, net	1,539,333	1,588,151
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	139,184	131,023
Asset retirement costs (non-landfill)
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	16,185	15,924
Landfill assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	185,678	182,276
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	502,507	499,159
Right-of-Use assets, finance leases	8,000	31,000
Camp equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	154,427	158,277
Vehicles
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	819,583	785,056
Right-of-Use assets, finance leases	43,800	2,400
Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,798,792	1,779,366
Right-of-Use assets, finance leases	9,100
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,920	6,054
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 20,928	$ 36,679