PROPERTY, PLANT AND EQUIPMENT

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

A summary of property, plant and equipment is as follows:


	December 31,
	2019		2018
Land	$	28,703	$	25,490
Landfills	578,814		544,663
Landfill operating lease contracts (1)	—		121,877
Finance lease right-of-use assets (2)	24,038		—
Buildings and improvements	161,316		150,885
Machinery and equipment	168,735		153,222
Rolling stock	183,145		163,758
Containers	143,948		123,383
	1,288,699		1,283,278
Less: accumulated depreciation and amortization (1)	(844,874)		(878,701)
	$	443,825	$	404,577

(1)Upon the adoption of Topic 842 effective January 1, 2019, landfill operating lease contracts payments that were previously capitalized as property, plant and equipment were prospectively reclassified, along with related accumulated depreciation, to operating lease right-of-use assets.

(2)Upon the adoption of Topic 842 effective January 1, 2019, property, plant and equipment pertaining to finance leases that were previously capitalized in other property, plant and equipment groupings were prospectively reclassified to finance lease right-of-use assets.

Depreciation expense for fiscal years 2019, 2018 and 2017 was $45,060, $35,351 and $32,131, respectively. Landfill amortization expense for fiscal years 2019, 2018 and 2017 was $27,512, $31,841 and $27,910, respectively. Depletion expense on landfill operating lease contracts for fiscal years 2018 and 2017 was $9,724 and $9,646, respectively, and was recorded in cost of operations. See Note 8, Leases for further disclosure over lease costs and other lease information.