Revenue - Sales by Major Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue
Total net sales	$ 145,345	$ 130,015	$ 408,867	$ 360,324
Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	86,866	77,350	242,866	222,857
Precast Concrete Products
Disaggregation of Revenue
Total net sales	38,642	28,856	96,795	67,477
Steel Products and Measurement
Disaggregation of Revenue
Total net sales	19,837	23,809	69,206	69,990
Rail Products and Global Friction Management | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	76,262	69,573	214,236	192,527
Technology Services and Solutions | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	10,604	7,777	28,630	30,330
Precast Concrete Buildings | Precast Concrete Products
Disaggregation of Revenue
Total net sales	20,127	15,525	50,338	41,306
Precast Infrastructure Products | Precast Concrete Products
Disaggregation of Revenue
Total net sales	18,515	13,331	46,457	26,171
Fabricated Steel Products | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	14,218	15,300	39,589	45,871
Coatings and Measurement | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	$ 5,619	$ 8,509	$ 29,617	$ 24,119