Property, Plant, and Equipment, net

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

10. Property, Plant and Equipment, net

Property, plant and equipment consists of the following (in millions):


	December 31,
	2019		2018
Cable-ships and submersibles	$	246.5	$	251.1
Equipment, furniture and fixtures, and software	214.1		148.0
Building and leasehold improvements	48.9		47.3
Land	36.8		32.8
Construction in progress	14.3		12.9
Plant and transportation equipment	13.5		12.0
	574.1		504.1
Less: Accumulated depreciation	168.3		127.8
Total	$	405.8	$	376.3

Depreciation expense was $52.3 million and $46.6 million for the years ended December 31, 2019 and 2018, respectively. These amounts included $9.1 million and $7.0 million of depreciation expense recognized within cost of revenue for the years ended December 31, 2019 and 2018, respectively.

As of December 31, 2019 and 2018 total net book value of equipment, cable-ships, and submersibles under capital leases consisted of $35.1 million and $40.0 million, respectively.

For the year ended December 31, 2019, our Marine Services segment recorded an impairment expense of $0.6 million, due to the under-utilization of assets on one of the segment's barges. For the year ended December 31, 2018, our Energy segment recorded an impairment expense of $0.7 million, of which $0.4 million was due to station performance and $0.3 million was related to the abandonment of a station development project.