v3.26.1
Earnings Per Common Share - Schedule of Earnings Per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Numerator for basic and diluted earnings per common share:        
Net income attributable to L.B. Foster Company $ 3,112 $ 2,885 $ 4,612 $ 775
Denominator:        
Weighted average shares outstanding (in shares) 10,343 10,439 10,271 10,489
Denominator for basic earnings per common share (in shares) 10,343 10,439 10,271 10,489
Effect of dilutive securities:        
Stock compensation plans (in shares) 265 414 326 456
Dilutive potential common shares (in shares) 265 414 326 456
Denominator for diluted earnings per common share - adjusted weighted average shares outstanding (in shares) 10,608 10,853 10,597 10,945
Basic earnings per common share (in USD per share) $ 0.30 $ 0.28 $ 0.45 $ 0.07
Diluted earnings per common share (in USD per share) $ 0.29 $ 0.27 $ 0.44 $ 0.07