Business Description	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Description	Business DescriptionOP Bancorp (the “Company”) is a California corporation whose common stock is quoted on the Nasdaq Global Market under the ticker symbol, “OPBK.” The Company was formed to acquire 100% of the voting equity of Open Bank (the “Bank”) and commenced operation as a bank holding company on June 1, 2016. This transaction was treated as an internal reorganization as all shareholders of the Bank became shareholders of the Company. The Company has no operations other than ownership of the Bank. The Bank is a California state-chartered and FDIC-insured financial institution, which began its operations on June 10, 2005. Headquartered in downtown Los Angeles, California, the Bank operates primarily in the traditional banking business arena that includes accepting deposits and making loans and investments. The Bank’s primary deposit products are demand and time deposits, and the primary lending products are commercial business loans to small to medium sized businesses. The Bank is operating with nine full-service branches, eight of which are located in California, in Downtown Los Angeles, Los Angeles Fashion District, Los Angeles Koreatown, Gardena, Buena Park and Santa Clara, and one full-service branch is located in Carrollton, Texas. The Bank also has four loan production offices in Atlanta, Georgia, Aurora, Colorado, and Lynwood and Seattle, Washington.