Acquisitions and Divestitures - Schedule of Business Acquisition, Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Diluted earnings from continuing operations per common share (usd per share)	$ (4.25)	$ 0.33
VanHooseCo
Business Acquisition [Line Items]
Net sales	$ 522,997	$ 540,359
Net (loss) income attributable to L.B. Foster Company	$ (44,564)	$ 2,223
Diluted earnings from continuing operations per common share (usd per share)	$ (4.25)	$ 0.33
Diluted (loss) earnings per share, Pro forma (usd per share)	$ (4.16)	$ 0.21