Business Segments (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Capital Charges Rate	1.00%
Segment Reporting, Factors Used to Identify Entity's Reportable Segments	The Company is a leading manufacturer and distributor of products and services for transportation and energy infrastructure. The Company is organized and evaluated by product group, which is the basis for identifying reportable segments. Each segment represents a revenue-producing component of the Company for which separate financial information is produced internally that is subject to evaluation by the Company's chief operating decision maker in deciding how to allocate resources. Each segment is evaluated based upon its segment profit contribution to the Company's consolidated results. The Company markets its products directly in all major industrial areas of the United States, Canada, and Europe, primarily through an internal sales force.The Company's Rail Products and Services segment provides a full line of new and used rail, trackwork, and accessories to railroads, mines, and other customers in the rail industry. The Rail segment also designs and produces insulated rail joints, power rail, track fasteners, concrete railroad ties, coverboards, and special accessories for mass transit and other rail systems. In addition, the Rail Products and Services segment engineers, manufactures, and assembles friction management products and railway wayside data collection and management systems. The Company's Construction Products segment sells and rents steel sheet piling, H-bearing pile, and other piling products for foundation and earth retention requirements. The Company's Fabricated Bridge Products division sells bridge decking, bridge railing, structural steel fabrications, expansion joints, bridge forms, and other products for highway construction and repair. The concrete products businesses produce precast concrete buildings and a variety of specialty precast concrete products.The Company's Tubular and Energy Services segment provides pipe coatings for natural gas pipelines and utilities, upstream test and inspection services, and precision measurement systems for the oil and gas market, and produces threaded pipe products for the oil and gas markets as well as industrial water well and irrigation markets.
Segment Reporting, Measurement for Transactions Between Reportable Segments	The following table illustrates net sales, profit (loss), assets, depreciation/amortization, and expenditures for long-lived assets of the Company by segment for the years ended or at December 31, 2016, 2015, and 2014. Segment profit is the earnings from operations before income taxes and includes internal cost of capital charges for net assets used in the segment at a rate of generally 1% per month excluding recently acquired businesses. The internal cost of capital charges are eliminated during the consolidation process. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies except that the Company accounts for inventory on a First-In, First-Out ("FIFO") basis at the segment level compared to a Last-In, First-Out ("LIFO") basis at the consolidated level
Customer 1 - 10% of Sales [Member]
Segment Reporting Information [Line Items]
Revenues	$ 0	$ 0	$ 0