Revenue Recognition Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 118,021	$ 105,686	$ 231,551	$ 205,840
Aerospace and Defense [Member]
Disaggregation of Revenue [Line Items]
Revenues	6,024	4,675	11,127	9,332
Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	22,773	19,214	43,129	36,326
Medical [Member]
Disaggregation of Revenue [Line Items]
Revenues	9,793	7,474	19,034	14,288
Telecommunications & IT [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,525	5,602	10,050	10,780
Transportation [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 73,906	$ 68,721	$ 148,211	$ 135,114