Commitments and Contingent Liabilites (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	168 Months Ended
	Dec. 31, 2011 item	Mar. 31, 2015	Dec. 31, 2014
Product Liability Contingency [Line Items]
Concrete Ties Manufactured	3,000,000
Standard Product Warranty Accrual		$ 10,344	$ 11,500
Environmental and litigation reserves		6,773	3,344
Reserve for Concrete Ties [Member]
Product Liability Contingency [Line Items]
Standard Product Warranty Accrual		$ 9,090	$ 10,331
The UPRR [Member]
Product Liability Contingency [Line Items]
Concrete Ties Manufactured	1,600,000