Summary of Significant Accounting Policies - Revision Adjustment to Consolidated Balance Sheets (Details) - USD ($) $ / shares in Units, $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 2,560	$ 2,882
Accounts receivable - net (Note 6)	53,484	82,455
Contract assets (Note 4)	29,489	33,613
Inventories - net (Note 7)	73,111	75,721
Other current assets	8,711	11,061
Total current assets	167,355	205,732
Property, plant, and equipment - net (Note 8)	75,579	85,344
Operating lease right-of-use assets - net (Note 9)	14,905	17,291
Other assets:
Goodwill (Note 5)	32,587	30,733	$ 20,152
Other intangibles - net (Note 5)	19,010	23,831
Other assets	2,965	2,379
TOTAL ASSETS	312,401	365,310
Current liabilities:
Accounts payable	39,500	48,782
Deferred revenue (Note 4)	12,479	19,452
Accrued payroll and employee benefits	16,978	10,558
Current portion of accrued settlement (Note 18)	8,000	8,000
Current maturities of long-term debt (Note 10)	102	127
Other accrued liabilities	17,442	16,192
Total current liabilities	94,501	103,111
Long-term debt (Note 10)	55,171	91,752
Deferred tax liabilities (Note 14)	1,232	3,109
Long-term operating lease liabilities (Note 9)	11,865	14,163
Other long-term liabilities	6,797	7,577
Stockholders’ equity:
Common stock, par value $0.01, authorized 20,000,000 shares; shares issued at December 31, 2023 and December 31, 2022, 11,115,779; shares outstanding at December 31, 2023 and December 31, 2022, 10,733,935 and 10,776,827, respectively (Note 11)	111	111
Paid-in capital	43,111	41,303
Retained earnings	124,633	123,169
Treasury stock - at cost, common stock, shares at December 31, 2023 and December 31, 2022, 381,844 and 338,952, respectively (Note 11)	(6,494)	(6,240)
Accumulated other comprehensive loss (Note 12)	(19,250)	(21,165)
Total L.B. Foster Company stockholders’ equity	142,111	137,178
Noncontrolling interest	724	420
Total stockholders’ equity	142,835	137,598	$ 183,610
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 312,401	$ 365,310
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares issued (in shares)	11,115,779	11,115,779
Common Stock, Shares, Outstanding	10,733,935	10,776,827
Treasury stock shares - at cost, common stock (in shares)	381,844	338,952
As Previously Reported
Current assets:
Cash and cash equivalents	$ 2,560
Accounts receivable - net (Note 6)	53,484
Contract assets (Note 4)	29,489
Inventories - net (Note 7)	73,496
Other current assets	8,961
Total current assets	167,990
Property, plant, and equipment - net (Note 8)	75,999
Operating lease right-of-use assets - net (Note 9)	14,905
Other assets:
Goodwill (Note 5)	32,587
Other intangibles - net (Note 5)	19,010
Other assets	2,715
TOTAL ASSETS	313,206
Current liabilities:
Accounts payable	40,305
Deferred revenue (Note 4)	12,479
Accrued payroll and employee benefits	16,978
Current portion of accrued settlement (Note 18)	8,000
Current maturities of long-term debt (Note 10)	102
Other accrued liabilities	17,442
Total current liabilities	95,306
Long-term debt (Note 10)	55,171
Deferred tax liabilities (Note 14)	1,232
Long-term operating lease liabilities (Note 9)	11,865
Other long-term liabilities	6,797
Stockholders’ equity:
Common stock, par value $0.01, authorized 20,000,000 shares; shares issued at December 31, 2023 and December 31, 2022, 11,115,779; shares outstanding at December 31, 2023 and December 31, 2022, 10,733,935 and 10,776,827, respectively (Note 11)	111
Paid-in capital	43,111
Retained earnings	124,633
Treasury stock - at cost, common stock, shares at December 31, 2023 and December 31, 2022, 381,844 and 338,952, respectively (Note 11)	(6,494)
Accumulated other comprehensive loss (Note 12)	(19,250)
Total L.B. Foster Company stockholders’ equity	142,111
Noncontrolling interest	724
Total stockholders’ equity	142,835
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	313,206
Adjustments
Current assets:
Cash and cash equivalents	0
Accounts receivable - net (Note 6)	0
Contract assets (Note 4)	0
Inventories - net (Note 7)	(385)
Other current assets	(250)
Total current assets	(635)
Property, plant, and equipment - net (Note 8)	(420)
Operating lease right-of-use assets - net (Note 9)	0
Other assets:
Goodwill (Note 5)	0
Other intangibles - net (Note 5)	0
Other assets	250
TOTAL ASSETS	(805)
Current liabilities:
Accounts payable	(805)
Deferred revenue (Note 4)	0
Accrued payroll and employee benefits	0
Current portion of accrued settlement (Note 18)	0
Current maturities of long-term debt (Note 10)	0
Other accrued liabilities	0
Total current liabilities	(805)
Long-term debt (Note 10)	0
Deferred tax liabilities (Note 14)	0
Long-term operating lease liabilities (Note 9)	0
Other long-term liabilities	0
Stockholders’ equity:
Common stock, par value $0.01, authorized 20,000,000 shares; shares issued at December 31, 2023 and December 31, 2022, 11,115,779; shares outstanding at December 31, 2023 and December 31, 2022, 10,733,935 and 10,776,827, respectively (Note 11)	0
Paid-in capital	0
Retained earnings	0
Treasury stock - at cost, common stock, shares at December 31, 2023 and December 31, 2022, 381,844 and 338,952, respectively (Note 11)	0
Accumulated other comprehensive loss (Note 12)	0
Total L.B. Foster Company stockholders’ equity	0
Noncontrolling interest	0
Total stockholders’ equity	0
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ (805)