XML 7 R1.htm IDEA: XBRL DOCUMENT
v3.25.3

Document and Entity Information - shares | 9 Months Ended |
--- | --- | ---
Sep. 30, 2025 | Oct. 27, 2025
Cover [Abstract] |  |
Document Type | 10-Q |
Amendment Flag | false |
Document Period End Date | Sep. 30, 2025 |
Document Fiscal Year Focus | 2025 |
Document Fiscal Period Focus | Q3 |
Entity Registrant Name | FIRST US BANCSHARES INC |
Entity Central Index Key | 0000717806 |
Current Fiscal Year End Date | --12-31 |
Entity Filer Category | Non-accelerated Filer |
Entity Small Business | true |
Entity Emerging Growth Company | false |
Entity Common Stock, Shares Outstanding |  | 5,766,888
Entity Current Reporting Status | Yes |
Entity Interactive Data Current | Yes |
Entity Shell Company | false |
Document Quarterly Report | true |
Document Transition Report | false |
Entity File Number | 000-14549 |
Entity Incorporation, State or Country Code | DE |
Entity Tax Identification Number | 63-0843362 |
Entity Address, Address Line One | 3291 U.S. Highway 280 |
Entity Address, City or Town | Birmingham |
Entity Address, State or Province | AL |
Entity Address, Postal Zip Code | 35243 |
City Area Code | 205 |
Local Phone Number | 582-1200 |
Title of 12(b) Security | Common Stock, $0.01 par value |
Trading Symbol | FUSB |
Security Exchange Name | NASDAQ |

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