Revenue - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue
Total net sales	$ 98,794	$ 116,080
Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	63,710	66,232
Precast Concrete Products
Disaggregation of Revenue
Total net sales	15,010	12,678
Steel Products and Measurement
Disaggregation of Revenue
Total net sales	20,074	37,170
Rail Products and Global Friction Management | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	51,651	55,309
Technology Services and Solutions | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	12,059	10,923
Precast Concrete Buildings | Precast Concrete Products
Disaggregation of Revenue
Total net sales	9,970	10,283
Other Precast Concrete Products | Precast Concrete Products
Disaggregation of Revenue
Total net sales	5,040	2,395
Fabricated Steel Products | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	12,604	27,721
Coatings and Measurement | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	$ 7,470	$ 9,449