Business Description	12 Months Ended
Dec. 31, 2019
Business Description [Abstract]
Business Description	NOTE 1 - BUSINESS DESCRIPTION RBB Bancorp is a financial holding company registered under the Bank Holding Company Act of 1956, as amended. RBB Bancorp’s principal business is to serve as the holding company for its wholly-owned banking subsidiaries, Royal Business Bank ("Bank") and RBB Asset Management Company ("RAM"), collectively referred to herein as "the Company". At December 31, 2019, the Company had total assets of $2.8 billion, gross consolidated loans (held for investment and held for sale) of $2.3 billion, total deposits of $2.2 billion and total stockholders' equity of $407.7 million. On July 31, 2017, the Company completed its initial public offering of 3,750,000 shares at a price to the public of $23.00 per share. The Company’s stock trades on the Nasdaq Global Select Market under the symbol “RBB”. The Bank provides business banking services to the Chinese-American communities in Los Angeles County, Orange County, Ventura County and in Las Vegas and New York City metropolitan area, including remote deposit, E-banking, mobile banking, commercial and investor real estate loans, business loans and lines of credit, Small Business Administration (“SBA”) 7A and 504 loans, mortgage loans, trade finance and a full range of depository accounts. The Company operates full-service banking offices in Arcadia, Cerritos, Diamond Bar, Irvine, Los Angeles, Monterey Park, Oxnard, Rowland Heights, San Gabriel, Silver Lake, Torrance, West Los Angeles, and Westlake Village, California; Las Vegas, Nevada; and Manhattan, Brooklyn, Flushing, and Elmhurst, New York. The Company's primary source of revenue is providing loans to customers, who are predominately small and middle-market businesses and individuals. The Company generates its revenue primarily from interest received on loans and leases and, to a lesser extent, from interest received on investment securities. The Company also derives income from noninterest sources, such as fees received in connection with various lending and deposit services, loan servicing, gain on sales of loans and wealth management services. The Company’s principle expenses include interest expense on deposits and subordinated debentures, and operating expenses, such as salaries and employee benefits, occupancy and equipment, data processing, and income tax expense. As part of the FAIC acquisition, the Company acquired FAIB Capital Corp. (FAICC) that was formed on January 29, 2014. FAICC is a real estate investment trust subsidiary of the Bank. The Company has completed five acquisitions from July 8, 2011 through October 15, 2018, including the acquisition of First American International Corp. (“FAIC”) and its wholly-owned subsidiary, First American International Bank (“FAIB”), in which the FAIC acquisition closed on October 15, 2018. FAIB operated three branches in Queens, two in Manhattan, and two in Brooklyn, New York with an operating center and loan production offices in Brooklyn and an administrative center in Manhattan. As part of the FAIC acquisition, the Company acquired FAIB Capital Corp. (“FAICC”) that was formed on January 29, 2014. FAICC is a real estate investment trust subsidiary of the Bank. See Note 3 – Acquisition, for more information about the FAIC acquisition transactions. All of the Company’s acquisitions have been accounted for using the acquisition method of accounting and, accordingly, the operating results of the acquired entities have been included in the consolidated financial statements from their respective acquisition dates.

Business Description

12 Months Ended

Dec. 31, 2019

NOTE 1 - BUSINESS DESCRIPTION

RBB Bancorp is a financial holding company registered under the Bank Holding Company Act of 1956, as amended. RBB Bancorp’s principal business is to serve as the holding company for its wholly-owned banking subsidiaries, Royal Business Bank ("Bank") and RBB Asset Management Company ("RAM"), collectively referred to herein as "the Company". At December 31, 2019, the Company had total assets of $2.8 billion, gross consolidated loans (held for investment and held for sale) of $2.3 billion, total deposits of $2.2 billion and total stockholders' equity of $407.7 million. On July 31, 2017, the Company completed its initial public offering of 3,750,000 shares at a price to the public of $23.00 per share. The Company’s stock trades on the Nasdaq Global Select Market under the symbol “RBB”.

The Bank provides business banking services to the Chinese-American communities in Los Angeles County, Orange County, Ventura County and in Las Vegas and New York City metropolitan area, including remote deposit, E-banking, mobile banking, commercial and investor real estate loans, business loans and lines of credit, Small Business Administration (“SBA”) 7A and 504 loans, mortgage loans, trade finance and a full range of depository accounts.

The Company operates full-service banking offices in Arcadia, Cerritos, Diamond Bar, Irvine, Los Angeles, Monterey Park, Oxnard, Rowland Heights, San Gabriel, Silver Lake, Torrance, West Los Angeles, and Westlake Village, California; Las Vegas, Nevada; and Manhattan, Brooklyn, Flushing, and Elmhurst, New York. The Company's primary source of revenue is providing loans to customers, who are predominately small and middle-market businesses and individuals.

The Company generates its revenue primarily from interest received on loans and leases and, to a lesser extent, from interest received on investment securities. The Company also derives income from noninterest sources, such as fees received in connection with various lending and deposit services, loan servicing, gain on sales of loans and wealth management services. The Company’s principle expenses include interest expense on deposits and subordinated debentures, and operating expenses, such as salaries and employee benefits, occupancy and equipment, data processing, and income tax expense.

As part of the FAIC acquisition, the Company acquired FAIB Capital Corp. (FAICC) that was formed on January 29, 2014. FAICC is a real estate investment trust subsidiary of the Bank.

The Company has completed five acquisitions from July 8, 2011 through October 15, 2018, including the acquisition of First American International Corp. (“FAIC”) and its wholly-owned subsidiary, First American International Bank (“FAIB”), in which the FAIC acquisition closed on October 15, 2018. FAIB operated three branches in Queens, two in Manhattan, and two in Brooklyn, New York with an operating center and loan production offices in Brooklyn and an administrative center in Manhattan. As part of the FAIC acquisition, the Company acquired FAIB Capital Corp. (“FAICC”) that was formed on January 29, 2014. FAICC is a real estate investment trust subsidiary of the Bank. See Note 3 – Acquisition, for more information about the FAIC acquisition transactions. All of the Company’s acquisitions have been accounted for using the acquisition method of accounting and, accordingly, the operating results of the acquired entities have been included in the consolidated financial statements from their respective acquisition dates.