Description of Business	12 Months Ended
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	1. DESCRIPTION OF BUSINESS First US Bancshares, Inc., a Delaware corporation (“Bancshares” and, together with its subsidiary, the “Company”), is a bank holding company formed in 1983 registered under the Bank Holding Company Act of 1956, as amended (the “BHCA”). Bancshares operates one wholly owned banking subsidiary, First US Bank, an Alabama banking corporation (the “Bank”). Bancshares and the Bank are headquartered in Birmingham, Alabama. Previously, the Bank operated two additional wholly owned subsidiaries, Acceptance Loan Company ("ALC") and FUSB Reinsurance, Inc., both of which were legally dissolved in 2023, and all remaining assets and liabilities of these entities were transferred to the Bank prior to December 31, 2023. The Bank conducts a general commercial banking business and offers banking services such as demand, savings, individual retirement account and time deposits, personal and commercial loans, safe deposit box services and remote deposit capture. The Bank operates and serves its customers through 15 full-service banking offices located in Birmingham, Butler, Calera, Centreville, Gilbertown, Grove Hill, Harpersville, Jackson, Thomasville, Tuscaloosa and Woodstock, Alabama; Knoxville and Powell, Tennessee; and Rose Hill, Virginia; as well as loan production offices in Mobile, Alabama and the Chattanooga, Tennessee area. The Bank provides a wide range of commercial banking services to small- and medium-sized businesses, property managers, business executives, professionals and other individuals. The Bank also performs indirect lending through third-party retailers and currently conducts this lending in 17 states, including Alabama, Arkansas, Florida, Georgia, Indiana, Iowa, Kansas, Kentucky, Mississippi, Missouri, Nebraska, North Carolina, Oklahoma, South Carolina, Tennessee, Texas and Virginia. The Bank is the Company’s only reportable operating segment upon which management makes decisions regarding how to allocate resources and assess performance.

Description of Business

12 Months Ended

Dec. 31, 2024

Organization, Consolidation and Presentation of Financial Statements [Abstract]

DESCRIPTION OF BUSINESS

First US Bancshares, Inc., a Delaware corporation (“Bancshares” and, together with its subsidiary, the “Company”), is a bank holding company formed in 1983 registered under the Bank Holding Company Act of 1956, as amended (the “BHCA”). Bancshares operates one wholly owned banking subsidiary, First US Bank, an Alabama banking corporation (the “Bank”). Bancshares and the Bank are headquartered in Birmingham, Alabama. Previously, the Bank operated two additional wholly owned subsidiaries, Acceptance Loan Company ("ALC") and FUSB Reinsurance, Inc., both of which were legally dissolved in 2023, and all remaining assets and liabilities of these entities were transferred to the Bank prior to December 31, 2023.

The Bank conducts a general commercial banking business and offers banking services such as demand, savings, individual retirement account and time deposits, personal and commercial loans, safe deposit box services and remote deposit capture. The Bank operates and serves its customers through 15 full-service banking offices located in Birmingham, Butler, Calera, Centreville, Gilbertown, Grove Hill, Harpersville, Jackson, Thomasville, Tuscaloosa and Woodstock, Alabama; Knoxville and Powell, Tennessee; and Rose Hill, Virginia; as well as loan production offices in Mobile, Alabama and the Chattanooga, Tennessee area. The Bank provides a wide range of commercial banking services to small- and medium-sized businesses, property managers, business executives, professionals and other individuals. The Bank also performs indirect lending through third-party retailers and currently conducts this lending in 17 states, including Alabama, Arkansas, Florida, Georgia, Indiana, Iowa, Kansas, Kentucky, Mississippi, Missouri, Nebraska, North Carolina, Oklahoma, South Carolina, Tennessee, Texas and Virginia. The Bank is the Company’s only reportable operating segment upon which management makes decisions regarding how to allocate resources and assess performance.