PROPERTY, PLANT, AND EQUIPMENT (Tables)

12 Months Ended

Dec. 31, 2015

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment

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

Asset Classification	Estimated Useful Life
Buildings and building improvements
Buildings	30–40 years
Leasehold and building improvements	2–40 years
Camp equipment	8–15 years
Vehicles	3–12 years
Equipment
Capitalized software and computer equipment	3–5 years
Solar equipment	20 years
Containers and railcars	15–20 years
All other equipment	8–20 years
Furniture and fixtures	5–8 years

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

	December 31, 2015		December 31, 2014
Land	$	100,582	$	98,507
Asset retirement costs (non-landfill)	12,434		10,871
Landfill assets	136,624		110,984
Buildings and improvements	344,209		338,242
Camp equipment	149,361		180,575
Vehicles	500,619		471,615
Equipment	1,328,915		1,302,424
Furniture and fixtures	5,337		5,517
Construction in progress	113,657		45,605
	2,691,738		2,564,340
Less - accumulated depreciation and amortization	1,159,271		1,005,506
Total property, plant and equipment, net	$	1,532,467	$	1,558,834