Revenue - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue
Total net sales	$ 131,515	$ 154,522	$ 230,309	$ 270,602
Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	81,797	88,782	145,507	155,014
Precast Concrete Products
Disaggregation of Revenue
Total net sales	23,611	20,073	38,621	32,751
Steel Products and Measurement
Disaggregation of Revenue
Total net sales	26,107	45,667	46,181	82,837
Rail Products and Global Friction Management | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	70,416	76,756	122,067	132,068
Technology Services and Solutions | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	11,381	12,026	23,440	22,946
Precast Concrete Buildings | Precast Concrete Products
Disaggregation of Revenue
Total net sales	15,811	16,349	25,781	26,630
Other Precast Concrete Products | Precast Concrete Products
Disaggregation of Revenue
Total net sales	7,800	3,724	12,840	6,121
Fabricated Steel Products | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	17,967	32,223	30,571	59,944
Coatings and Measurement | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	$ 8,140	$ 13,444	$ 15,610	$ 22,893