Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Mar. 03, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Document Transition Report	false
Entity File Number	001-38895
Entity Registrant Name	South Plains Financial, Inc.
Entity Central Index Key	0001163668
Entity Incorporation, State or Country Code	TX
Entity Tax Identification Number	75-2453320
Entity Address, Address Line One	5219 City Bank Parkway
Entity Address, City or Town	Lubbock
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	79407
City Area Code	806
Local Phone Number	792-7101
Title of 12(b) Security	Common Stock, par value $1.00 per share
Trading Symbol	SPFI
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	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Public Float			$ 309.2
Entity Common Stock, Shares Outstanding		17,693,639
Auditor Firm ID	410
Auditor Name	WEAVER AND TIDWELL, L.L.P.
Auditor Location	Fort Worth, Texas