Revenue - Timing of Transfer (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
Point in time
Disaggregation of Revenue
Total net sales	110,870	95,413	193,832	163,904
Over time
Disaggregation of Revenue
Total net sales	37,164	36,102	69,690	66,405
Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	91,616	81,797	156,000	145,507
Rail, Technologies, and Services | Point in time
Disaggregation of Revenue
Total net sales	75,923	65,872	129,757	115,038
Rail, Technologies, and Services | Over time
Disaggregation of Revenue
Total net sales	15,693	15,925	26,243	30,469
Precast Concrete Products
Disaggregation of Revenue
Total net sales	33,865	23,611	58,153	38,621
Precast Concrete Products | Point in time
Disaggregation of Revenue
Total net sales	14,540	8,577	27,942	12,840
Precast Concrete Products | Over time
Disaggregation of Revenue
Total net sales	19,325	15,034	30,211	25,781
Steel Products and Measurement
Disaggregation of Revenue
Total net sales	22,553	26,107	49,369	46,181
Steel Products and Measurement | Point in time
Disaggregation of Revenue
Total net sales	20,407	20,964	36,133	36,026
Steel Products and Measurement | Over time
Disaggregation of Revenue
Total net sales	$ 2,146	$ 5,143	$ 13,236	$ 10,155