Revenue - Timing of Transfer (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
Point in time
Disaggregation of Revenue
Total net sales	95,413	111,348	163,904	198,056
Over time
Disaggregation of Revenue
Total net sales	36,102	43,174	66,405	72,546
Rail, Technologies, and Services
Disaggregation of Revenue
Total net sales	81,797	88,782	145,507	155,014
Rail, Technologies, and Services | Point in time
Disaggregation of Revenue
Total net sales	65,872	71,711	115,038	123,755
Rail, Technologies, and Services | Over time
Disaggregation of Revenue
Total net sales	15,925	17,071	30,469	31,259
Precast Concrete Products
Disaggregation of Revenue
Total net sales	23,611	20,073	38,621	32,751
Precast Concrete Products | Point in time
Disaggregation of Revenue
Total net sales	8,577	5,195	12,840	9,931
Precast Concrete Products | Over time
Disaggregation of Revenue
Total net sales	15,034	14,878	25,781	22,820
Steel Products and Measurement
Disaggregation of Revenue
Total net sales	26,107	45,667	46,181	82,837
Steel Products and Measurement | Point in time
Disaggregation of Revenue
Total net sales	20,964	34,442	36,026	64,370
Steel Products and Measurement | Over time
Disaggregation of Revenue
Total net sales	$ 5,143	$ 11,225	$ 10,155	$ 18,467