Revenue - Revenue from External Customers by Geographic Areas (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Net sales	$ 546,076	$ 496,038
North America
Disaggregation of Revenue [Line Items]
Net sales	483,302	436,068
Pacific Rim
Disaggregation of Revenue [Line Items]
Net sales	39,180	42,071
Europe
Disaggregation of Revenue [Line Items]
Net sales	16,562	13,743
Other
Disaggregation of Revenue [Line Items]
Net sales	7,032	4,156
Energy
Disaggregation of Revenue [Line Items]
Net sales	222,779	185,685
Industrial
Disaggregation of Revenue [Line Items]
Net sales	180,111	201,196
Transportation
Disaggregation of Revenue [Line Items]
Net sales	$ 143,186	$ 109,157