Retirement Plans (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 contract	Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Number of retirement plans			5
Defined Benefit Plan Number			3
Active Defined Benefit Plan Number			1
Inactive Defined Benefit Plan Number			2
Defined Contribution Plan Number			2
Defined Contribution Plan, Cost Recognized	$ 585	$ 715	$ 1,769	$ 2,017
Salaried Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Description of Postemployment Benefits			The Company has a domestic defined contribution plan that covers all non-union hourly and all salaried employees (Salaried Plan). The Salaried Plan permits both pre-tax and after-tax employee contributions. Participants can contribute, subject to statutory limitations, between 1% and 75% of eligible pre-tax pay and between 1% and 100% of eligible after-tax pay. The Company's employer match is 100% of the first 1% of deferred eligible compensation and up to 50% of the next 6%, based on years of service, of deferred eligible compensation, for a total maximum potential match of 4%. The Company may also make discretionary contributions to the Salaried Plan.
Defined Contribution Plan, Cost Recognized	478	599	1,422	1,674
Union Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Description of Postemployment Benefits			The Company also has a domestic defined contribution plan for union hourly employees with contributions made by both the participants and the Company based on various formulas (Union Plan).
Defined Contribution Plan, Cost Recognized	18	23	53	59
Canadian Employees [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan Number			2
Description of Postemployment Benefits			Rail Technologies, maintains a defined contribution plan covering all non-union employees at its Montreal, Quebec, Canada location (Montreal Plan). Under the terms of the Montreal Plan, the employer may contribute 4% of each employee's compensation as a non-elective contribution and may also contribute 30% of the first 6% of each employee's compensation contributed to the Montreal Plan.
Defined Contribution Plan, Cost Recognized	28	30	88	89
United Kingdom Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss)	(57)	(58)	(171)	(165)
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year			264
Defined Benefit Plan, Contributions by Employer			191
Description of Postemployment Benefits			The subsidiary also maintains a defined contribution plan covering substantially all employees at its United Kingdom locations (U.K. Plan). Benefits under the U.K. Plan are provided under no formal written agreement. Under the terms of the defined contribution U.K. Plan, the employer may make non-elective contributions of between 3% and 10% of each employee's compensation.
Defined Contribution Plan, Cost Recognized	27	29	95	84
Burnaby Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Description of Postemployment Benefits			Finally, Rail Technologies maintains a defined contribution plan covering substantially all of the employees of L.B. Foster Rail Technologies, Corp. in Burnaby, British Columbia, Canada, a wholly-owned subsidiary of the Company (Burnaby Plan). Under the terms of the Burnaby Plan, the employer may contribute 4% of each employee's compensation as a non-elective contribution and may also contribute 30% of the first 6% of each employee's compensation contributed to the Burnaby Plan.
Defined Contribution Plan, Cost Recognized	34	34	111	111
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss)	(53)	(49)	(159)	(146)
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year			555
Defined Benefit Plan, Contributions by Employer			$ 332