Business Segments - Reconciliation of Revenue from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information
Total net sales	$ 98,794	$ 116,080
Operating loss	(2,287)	(661)
Operating Segments
Segment Reporting Information
Total net sales	98,794	116,080
Operating loss	(1,900)	1,185
Rail, Technologies, and Services
Segment Reporting Information
Total net sales	63,710	66,232
Rail, Technologies, and Services | Operating Segments
Segment Reporting Information
Total net sales	63,710	66,232
Operating loss	1,039	2,225
Precast Concrete Products
Segment Reporting Information
Total net sales	15,010	12,678
Precast Concrete Products | Operating Segments
Segment Reporting Information
Total net sales	15,010	12,678
Operating loss	(791)	(112)
Steel Products and Measurement
Segment Reporting Information
Total net sales	20,074	37,170
Steel Products and Measurement | Operating Segments
Segment Reporting Information
Total net sales	20,074	37,170
Operating loss	$ (2,148)	$ (928)