Cover - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Mar. 22, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38437
Entity Registrant Name	OP BANCORP
Entity Incorporation, State or Country Code	CA
Entity Tax Identification Number	81-3114676
Entity Address, Address Line One	1000 Wilshire Blvd
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	Los Angeles
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90017
City Area Code	213
Local Phone Number	892-9999
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	OPBK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Public Float			$ 101,500
Entity Common Stock, Shares Outstanding		14,956,399
Entity Central Index Key	0001722010
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false