Commitments and Contingent Liabilities (Narratives) (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) tie	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) tie	Dec. 31, 2013 tie	Dec. 31, 2012 USD ($)
Product Liability Contingency
Accrued warranty	$ 10,154	$ 8,682	$ 10,154
Concrete ties manufactured | tie		3,000,000
Warranty period							10 years
Reserve for Concrete Ties [Member]
Product Liability Contingency
Accrued warranty	7,574	$ 7,595	7,574
Product warranty expense		$ 21	204	$ 972
Warranty period							5 years
Uprr
Product Liability Contingency
Concrete ties manufactured | tie		1,600,000
Warranty period							5 years
Warranty ratio							1.5
Uprr | Reserve for Concrete Ties [Member]
Product Liability Contingency
Product warranty expense							$ 22,000
Litigation settlement, amount award to other party							$ 12,000
Cure period to claim					90 days
Increase in warranty accrual					$ 8,766
Ties excluded from warranty | tie					90,100
Two Thousand Five Contract
Product Liability Contingency
Concrete ties manufacturing ratio | tie		1.5
Replacement period for ties post sale		5 years
Warranty Policy
Product Liability Contingency
Warranty period							15 years
Warranty ratio							1
Warranty Policy | Uprr
Product Liability Contingency
Ties that did not meet warranty criteria | tie						170,000
Collective Action Complaint
Product Liability Contingency
Litigation settlement, amount award to other party	$ 900
Litigation settlement expense		$ 797	900
Tubular and Energy Services
Product Liability Contingency
Product warranty expense		839
Tubular and Energy Services | Collective Action Complaint | Adjustments
Product Liability Contingency
Litigation settlement expense		$ (103)
Rail Products and Services
Product Liability Contingency
Product warranty expense			$ 1,224