v3.25.4
First US Bancshares, Inc. (Parent Company Only) Financial Information - Statements of Balance Sheet (Detail) - USD ($)
$ in Thousands
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Balance Sheet Related Disclosures [Line Items]      
Cash on deposit $ 73,547 $ 47,216  
Other assets 9,474 11,022  
Total assets 1,154,785 1,101,086  
Other liabilities 7,704 7,282  
Long-term borrowings 10,945 10,872  
Shareholders’ equity 105,648 98,624 $ 90,593
Total liabilities and shareholders’ equity 1,154,785 1,101,086  
FUSB [Member]      
Balance Sheet Related Disclosures [Line Items]      
Cash on deposit 6,713 2,716  
Investment in subsidiaries 109,607 106,167  
Other assets 519 718  
Total assets 116,839 109,601  
Other liabilities 246 105  
Long-term borrowings 10,945 10,872  
Shareholders’ equity 105,648 98,624  
Total liabilities and shareholders’ equity $ 116,839 $ 109,601