Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Mar. 10, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-38280
Entity Registrant Name	Stellar Bancorp, Inc.
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	20-8339782
Entity Address, Address Line One	9 Greenway Plaza, Suite 110
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77046
City Area Code	713
Local Phone Number	210-7600
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	STEL
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 483.7
Entity Common Stock Shares Outstanding		52,974,885
Documents Incorporated by Reference	Portions of the Proxy Statement relating to the 2023 Annual Meeting of Shareholders of Stellar Bancorp, Inc., which will be filed within 120 days after December 31, 2022, are incorporated by reference into Part III, Items 10-14 of this Annual Report on Form 10-K.
Entity Central Index Key	0001473844
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY