PROPERTY, PLANT, AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2021

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Equipment

The Company depreciates and amortizes the capitalized cost of these assets, using the straight-line method as follows:

Asset Classification	Estimated Useful Life
Buildings and building improvements
Buildings	20-42 years
Leasehold and building improvements	2-45 years
Camp and lodging equipment	8-15 years
Vehicles	2-15 years
Equipment
Capitalized software and computer equipment	3-5 years
Containers and railcars	8-16 years
All other equipment	4-30 years
Furniture and fixtures	5-8 years

Property, plant and equipment consisted of the following (in thousands):

	December 31, 2021		December 31, 2020
Land	$	165,010	$	139,776
Asset retirement costs (non-landfill)	19,105		16,407
Landfill assets	205,873		191,687
Buildings and improvements (1)	551,795		509,804
Camp equipment	127,680		159,021
Vehicles (2)	912,836		844,026
Equipment (3)	2,092,395		1,807,235
Furniture and fixtures	6,444		7,082
Construction in progress	60,447		24,378
	4,141,585		3,699,416
Less - accumulated depreciation and amortization	2,278,410		2,174,118
Total property, plant and equipment, net	$	1,863,175	$	1,525,298

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(1) Balances inclusive of gross ROU assets classified as finance leases of $8.9 million in both periods.

(2) Balances inclusive of gross ROU assets classified as finance leases of $77.7 million and $47.2 million, respectively.

(3) Balances inclusive of gross ROU assets classified as finance leases of $9.3 million both periods.