Inventories (Tables)

12 Months Ended

Dec. 31, 2018

Inventory Disclosure [Abstract]

Inventories

Inventories as of December 31, 2018 and 2017 consist of the following amounts (in thousands):

	2018		2017
Raw materials and construction materials	$	30,006	$	23,924
Work in process	12,315		18,800
Inventories	$	42,321	$	42,724