PROPERTY, PLANT AND EQUIPMENT

3 Months Ended

Mar. 31, 2018

Property, Plant and Equipment [Abstract]

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



	March 31, 2018		December 31, 2017
Land	$	124,331	$	121,658
Asset retirement costs (non-landfill)	14,794		14,593
Landfill assets	145,177		144,539
Buildings and improvements	421,749		414,384
Camp equipment	165,104		170,012
Vehicles	676,749		617,959
Equipment	1,659,335		1,644,102
Furniture and fixtures	5,656		5,708
Construction in progress	47,034		57,618
	3,259,929		3,190,573
Less - accumulated depreciation and amortization	1,628,281		1,603,208
Total property, plant and equipment, net	$	1,631,648	$	1,587,365

Interest in the amount of $0.3 million and $0.1 million was capitalized to property, plant and equipment during the three months ended March 31, 2018 and March 31, 2017 respectively. Depreciation expense, inclusive of landfill amortization, was $65.6 million and $63.3 million for the three months ended March 31, 2018 and March 31, 2017, respectively.