Inventories

9 Months Ended

Sep. 30, 2019

Inventory Disclosure [Abstract]

Inventories

Inventories

Inventories are valued at the lower of cost or net realizable value. Cost is determined by the first-in, first-out (“FIFO”) method. We establish an allowance for excess and obsolete inventories based on product line changes, the feasibility of substituting parts and the need for supply and replacement parts.

The components of inventories are as follows:

	September 30, 2019		December 31, 2018
	(in thousands)
Raw materials	$	74,950	$	67,995
Work in process	2,271		4,060
Finished goods	5,602		6,767
Total, gross	82,823		78,822
Less:  Allowance for excess and obsolete inventories	(2,200)		(1,210)
Total, net	$	80,623	$	77,612

The related changes in the allowance for excess and obsolete inventories account are as follows:

	Three months ended				Nine months ended
	September 30, 2019		September 30, 2018		September 30, 2019		September 30, 2018
Allowance for excess and obsolete inventories:	(in thousands)
Balance, beginning of period	$	2,350	$	1,407	$	1,210	$	1,118
Provisions for excess and obsolete inventories	(150)		(263)		1,003		55
Inventories written off	—		(30)		(13)		(59)
Balance, end of period	$	2,200	$	1,114	$	2,200	$	1,114