Commitments and Contingent Liabilites (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Product Liability Contingency [Line Items]
Standard Product Warranty Accrual	$ 15,727,000	$ 6,632,000	$ 4,403,000
Reserve for Concrete Ties [Member]
Product Liability Contingency [Line Items]
Loss Contingency, Settlement Agreement, Consideration	12,000,000
Loss Contingency, Estimate of Possible Loss	22,000,000
Standard Product Warranty Accrual	14,837,000	5,160,000	1,966,000
Standard Product Warranty Accrual, Period Increase (Decrease)	23,019,000	3,469,000	750,000
Reserve for Environmental Costs [Member]
Product Liability Contingency [Line Items]
Estimated Litigation Liability	$ 2,141,000	$ 2,184,000