Acquisitions (Identifiable Intangible Assets Acquired) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended				9 Months Ended
	Dec. 31, 2013 L.B. Foster Ball Winch, Inc. [Member]	Dec. 31, 2013 L.B. Foster Ball Winch, Inc. [Member] Trade name [Member]	Dec. 31, 2013 L.B. Foster Ball Winch, Inc. [Member] Technology and customer relationships [Member]	Dec. 31, 2013 L.B. Foster Ball Winch, Inc. [Member] Non-compete agreements [Member]	Sep. 30, 2014 Carr Concrete Corporation [Member]	Sep. 30, 2014 Carr Concrete Corporation [Member] Trade name [Member]	Sep. 30, 2014 Carr Concrete Corporation [Member] Technology and customer relationships [Member]	Sep. 30, 2014 Carr Concrete Corporation [Member] Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$ 14,682	$ 723	$ 11,129	$ 2,830	$ 1,348	$ 613	$ 611	$ 124