CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Total net sales (Note 4)		$ 543,744	$ 497,497
Total cost of sales		431,700	407,886
Gross profit		112,044	89,611
Selling and administrative expenses		97,623	82,657
Amortization expense (Note 5)		5,314	6,144
Goodwill and long-lived assets impairment charges (Note 5)	$ 4,883	0	8,016
Operating income (loss)		9,107	(7,206)
Interest expense - net		5,528	3,340
Other expense (income) - net (Note 19)		2,635	(1,550)
Income (loss) before income taxes		944	(8,996)
Income tax (benefit) expense (Note 14)		(355)	36,681
Net income (loss)		1,299	(45,677)
Net loss attributable to noncontrolling interest		(165)	(113)
Net income (loss) attributable to L.B. Foster Company		$ 1,464	$ (45,564)
Basic earnings (loss) per common share (usd per share)		$ 0.14	$ (4.25)
Diluted earnings (loss) per common share (usd per share)		$ 0.13	$ (4.25)
Basic weighted average shares outstanding (in shares)		10,799,000	10,720,000
Diluted weighted average shares outstanding (in shares)		10,995,000	10,720,000
Sales of goods
Total net sales (Note 4)		$ 475,350	$ 436,821
Total cost of sales		368,197	355,106
Sales of services
Total net sales (Note 4)		68,394	60,676
Total cost of sales		$ 63,503	$ 52,780