CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 4,405	$ (2,171)
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustment		(1,497)	1,247
Unrealized gain (loss) on cash flow hedges, net of tax expense of $0		106	(418)
Reclassification of pension liability adjustments to earnings, net of tax expense of $4 and $2, respectively	[1]	25	40
Total comprehensive income (loss)		3,039	(1,302)
Less comprehensive (loss) income attributable to noncontrolling interest:
Net loss attributable to noncontrolling interest		(31)	(19)
Foreign currency translation adjustment		(17)	4
Amounts attributable to noncontrolling interest		(48)	(15)
Comprehensive income (loss) attributable to L.B. Foster Company		$ 3,087	$ (1,287)

[1] Reclassifications out of “Accumulated other comprehensive loss” for pension obligations are charged to “Selling and administrative expenses” within the Condensed Consolidated Statements of Operations.