Business Segments - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Segment Reporting Information
Assets	$ 397,364	$ 405,171
Operating Segments | Rail Products and Services
Segment Reporting Information
Assets	171,806	186,323
Operating Segments | Construction Products
Segment Reporting Information
Assets	99,894	83,049
Operating Segments | Tubular and Energy Services
Segment Reporting Information
Assets	71,157	77,320
Unallocated corporate assets
Segment Reporting Information
Assets	$ 54,507	$ 58,479