Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 108,646	$ 110,630	$ 317,069	$ 329,319
Revenue recognized over time
Disaggregation of Revenue [Line Items]
Revenues	3,857	3,455	11,341	9,203
Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Revenues	104,789	107,175	305,728	320,116
United States
Disaggregation of Revenue [Line Items]
Revenues	93,395	95,288	275,152	284,351
Asia
Disaggregation of Revenue [Line Items]
Revenues	2,816	1,928	6,555	6,789
Canada
Disaggregation of Revenue [Line Items]
Revenues	3,437	2,564	10,755	9,353
Europe
Disaggregation of Revenue [Line Items]
Revenues	4,327	4,457	14,128	14,605
Mexico
Disaggregation of Revenue [Line Items]
Revenues	1,682	1,031	3,519	2,137
Middle East
Disaggregation of Revenue [Line Items]
Revenues	1,317	4,602	4,382	9,958
Other
Disaggregation of Revenue [Line Items]
Revenues	$ 1,672	$ 760	$ 2,578	$ 2,126