Revenue - Sales by Major Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue
Total net sales	$ 148,034	$ 131,515	$ 263,522	$ 230,309
Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	91,616	81,797	156,000	145,507
Precast Concrete Products
Disaggregation of Revenue
Total net sales	33,865	23,611	58,153	38,621
Steel Products and Measurement
Disaggregation of Revenue
Total net sales	22,553	26,107	49,369	46,181
Rail Products and Global Friction Management | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	81,926	70,416	137,974	122,067
Technology Services and Solutions | Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	9,690	11,381	18,026	23,440
Precast Concrete Buildings | Precast Concrete Products
Disaggregation of Revenue
Total net sales	19,325	15,811	30,211	25,781
Precast Infrastructure Products | Precast Concrete Products
Disaggregation of Revenue
Total net sales	14,540	7,800	27,942	12,840
Fabricated Steel Products | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	14,854	17,967	25,371	30,571
Coatings and Measurement | Steel Products and Measurement
Disaggregation of Revenue
Total net sales	$ 7,699	$ 8,140	$ 23,998	$ 15,610