Business Segments - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Segment Reporting Information
Assets	$ 365,422	$ 342,595
Operating Segments | Rail, Technologies, and Services
Segment Reporting Information
Assets	174,857	171,608
Operating Segments | Precast Concrete Products
Segment Reporting Information
Assets	58,203	48,740
Operating Segments | Steel Products and Measurement
Segment Reporting Information
Assets	60,267	58,377
Unallocated corporate assets
Segment Reporting Information
Assets	$ 72,095	$ 63,870