Properties And Equipment

12 Months Ended

Dec. 31, 2020

12. Properties and Equipment

A summary of properties and equipment follows (in thousands):


		December 31,
		2020		2019
Land	$	9,385	$	8,360
Buildings and building improvements		117,419		109,404
Transportation equipment		68,379		41,897
Machinery and equipment		129,835		123,102
Computer software		62,138		57,508
Furniture and fixtures		78,507		79,792
Projects under development		15,537		25,840
Total properties and equipment		481,200		445,903
Less accumulated depreciation		(293,380)		(270,140)
Net properties and equipment	$	187,820	$	175,763

The net book value of computer software at December 31, 2020 and 2019, was $8.9 million and $9.6 million, respectively. Depreciation expense for computer software was $5.5 million, $4.6 million and $5.4 million for the years ended December 31, 2020, 2019 and 2018, respectively.