Note 6. Fixed Assets

The following table summarizes our fixed assets by category at December 31:



(in thousands)	2017			2016
Software	$	129,553		$	124,093
Equipment	13,858			11,771
Land, buildings, and building improvements	7,627			7,627
Leasehold improvements	1,375			1,375
Projects in progress	21,898			17,812
Construction in progress	26,312			9,622
Total fixed assets, gross	200,623			172,300
Less: Accumulated depreciation	(117,474		)	(103,158		)
Fixed assets, net	$	83,149		$	69,142

Projects in progress include certain computer software and software developments costs for internal use that are not yet subject to amortization.

In 2016, we announced the construction of a new office building that will serve as part of our principal headquarters. The costs associated with this project are included in construction in progress. Capitalized interest included in construction in progress was $0.6 million for 2017. There was no capitalized interest in 2016. The project is expected to span approximately three years and is financed using a senior secured draw term loan credit facility. See Note 7, "Borrowing Arrangements".

For the years ended December 31, 2017, 2016 and 2015, depreciation and amortization of fixed assets totaled $14.8 million, $15.1 million and $15.9 million, respectively, and is included in all other operating expenses in the Statements of Operations.