Property, Plant and Equipment, net
 12 Months Ended
Dec. 31, 2016
Property, Plant and Equipment [Abstract]  
Property, Plant and Equipment, net
6. Property, Plant and Equipment, net

Property, plant and equipment, net, consisted of the following (in thousands):
 
December 31,
 
2016
 
2015
Compression equipment, facilities and other fleet assets
$
1,480,568

 
$
1,527,328

Land and buildings
110,378

 
117,247

Transportation and shop equipment
140,128

 
144,413

Other
95,817

 
99,035

 
1,826,891

 
1,888,023

Accumulated depreciation
(1,029,082
)
 
(1,029,835
)
Property, plant and equipment, net
$
797,809

 
$
858,188



Depreciation expense was $134.2 million, $149.5 million and $163.7 million during the years ended December 31, 2016, 2015 and 2014, respectively. During the year ended December 31, 2016, we retired $81.9 million of fully depreciated capitalized installation costs relating to a contract operations project in the Eastern Hemisphere that early terminated operations in January 2016. Assets under construction of $39.6 million and $65.6 million were primarily included in compression equipment, facilities and other fleet assets at December 31, 2016 and 2015, respectively. We capitalized $0.3 million and $0.1 million of interest related to construction in process during the years ended December 31, 2016 and 2015, respectively.