Business Segments - Reconciliation of Revenue from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information
Total net sales	$ 131,515	$ 154,522	$ 230,309	$ 270,602
Operating profit	2,480	4,924	193	4,263
Operating Segments
Segment Reporting Information
Total net sales	131,515	154,522	230,309	270,602
Operating profit	4,635	7,619	2,735	8,797
Rail, Technologies, and Services
Segment Reporting Information
Total net sales	81,797	88,782	145,507	155,014
Rail, Technologies, and Services | Operating Segments
Segment Reporting Information
Total net sales	81,797	88,782	145,507	155,014
Operating profit	3,998	5,657	5,037	7,879
Precast Concrete Products
Segment Reporting Information
Total net sales	23,611	20,073	38,621	32,751
Precast Concrete Products | Operating Segments
Segment Reporting Information
Total net sales	23,611	20,073	38,621	32,751
Operating profit	(125)	1,148	(916)	1,031
Steel Products and Measurement
Segment Reporting Information
Total net sales	26,107	45,667	46,181	82,837
Steel Products and Measurement | Operating Segments
Segment Reporting Information
Total net sales	26,107	45,667	46,181	82,837
Operating profit	$ 762	$ 814	$ (1,386)	$ (113)