Cover - USD ($)	12 Months Ended
	Dec. 31, 2023	Sep. 24, 2024	Jun. 30, 2023
Cover [Abstract]
Entity Registrant Name	Smith-Midland Corporation
Entity Central Index Key	0000924719
Document Type	10-K/A
Amendment Flag	true
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Well Known Seasoned Issuer	No
Entity Small Business	true
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Document Period End Date	Dec. 31, 2023
Entity Filer Category	Non-accelerated Filer
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2023
Entity Common Stock Shares Outstanding		5,345,759
Entity Public Float			$ 73,135,252
Entity File Number	1-13752
Entity Incorporation State Country Code	DE
Entity Tax Identification Number	54-1727060
Entity Address Address Line 1	P.O. Box 300
Entity Address Address Line 2	5119 Catlett Road
Entity Address City Or Town	Midland
Entity Address State Or Province	VA
Entity Address Postal Zip Code	22728
City Area Code	540
Local Phone Number	439-3266
Security 12b Title	Common Stock, $0.01 par value per share
Trading Symbol	SMID
Security Exchange Name	NASDAQ
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Icfr Auditor Attestation Flag	false
Amendment Description	Smith-Midland Corporation. (the “Company”) is filing this Amendment No. 1 on Form 10-K/A (this “Amendment No. 1”) to amend its Annual Report on Form 10-K for the fiscal year ended December 31, 2023, as filed with the Securities and Exchange Commission (the “SEC”) on May 23, 2024 (the “Original Form 10-K”). This Amendment No. 1 is being filed solely in order to (i) delete the hyperlink for Exhibit 3.2 which inadvertently linked a prior set of the Company’s By-Laws, and (ii) replace Exhibit 3.2 with a current version of the Company’s Amended and Restated By-Laws.  Exhibit 3.2 was originally filed as an Exhibit to a Form 8-K filed with the Securities and Exchange Commission on October 31, 2023. In accordance with the rules of the SEC, updated certifications pursuant to Section 302 of the Sarbanes-Oxley Act 2002 are being filed as Exhibits 31.1 and 31.2 and an updated certification pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 is being filed as Exhibits 32.1 to this Amendment No. 1. Since financial statements are not included in this Amendment No. 1 and this Amendment No. 1 does not contain or amend any disclosure with respect to Items 307 and 308 of Regulation S-K, paragraphs 3, 4, and 5 of the certifications have been omitted.  Except as noted above, no other modifications or changes have been made to the Original Form 10-K or the Company’s consolidated financial statements or the notes thereto included therein. This Amendment No. 1 does not reflect the effect of any events subsequent to the filing of the Original Form 10-K and does not modify or update in any way any other disclosures made in the Original Form 10-K.  Accordingly, this Amendment No. 1 should be read in conjunction with the Original Form 10-K and the Company’s other filings made with the SEC.