PROPERTY, PLANT, AND EQUIPMENT

12 Months Ended

Dec. 31, 2018

Property, Plant and Equipment [Abstract]

PROPERTY, PLANT, AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT

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

	December 31, 2018		December 31, 2017
Land	$	123,734	$	121,658
Asset retirement costs (non-landfill)	15,148		14,593
Landfill assets	154,918		144,539
Buildings and improvements	440,188		414,384
Camp and lodging equipment	152,998		170,012
Vehicles	721,735		617,959
Equipment	1,697,490		1,644,102
Furniture and fixtures	5,453		5,708
Construction in progress	20,931		57,618
	3,332,595		3,190,573
Less - accumulated depreciation and amortization	1,770,617		1,603,208
Total property, plant and equipment, net	$	1,561,978	$	1,587,365

Interest in the amount of $0.6 million, $0.6 million and $5.5 million was capitalized to property, plant and equipment during the years ended December 31, 2018, 2017 and 2016, respectively. Depreciation expense, inclusive of landfill amortization was $264.3 million, $251.4 million and $247.0 million for the years ended December 31, 2018, 2017 and 2016, respectively.