PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION, Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities [Abstract]
Net income	$ 62,745	$ 58,240	$ 58,614
Adjustments [Abstract]
Stock based compensation	2,157	2,753	1,639
Net cash provided by operating activities	58,539	123,590	96,271
Cash flows from financing activities [Abstract]
Payments to tax authorities for stock-based compensation	(731)	(1,168)	(625)
Payments to repurchase common stock	(17,763)	(22,699)	(9,227)
Cash dividends paid on common stock	(8,745)	(8,012)	(5,385)
Net cash provided by financing activities	180,112	33,329	250,084
Net change in cash and cash equivalents	95,275	(251,938)	186,514
Beginning cash and cash equivalents	234,883	486,821	300,307
Ending cash and cash equivalents	330,158	234,883	486,821
South Plains Financial, Inc. [Member]
Cash flows from operating activities [Abstract]
Net income	62,745	58,240	58,614
Adjustments [Abstract]
Equity in undistributed subsidiary income	(34,932)	(23,715)	(15,401)
Amortization of debt issuance costs	186	186	186
Stock based compensation	2,157	2,753	1,639
Change in other assets	(3,378)	(3,201)	(1,765)
Change in other liabilities	1,004	369	317
Net cash provided by operating activities	27,782	34,632	43,590
Cash flows from financing activities [Abstract]
Repayments of long-term borrowings	(12,372)	0	0
Payments to tax authorities for stock-based compensation	(731)	(1,168)	(625)
Payments to repurchase common stock	(17,763)	(22,699)	(9,227)
Cash dividends paid on common stock	(8,745)	(8,012)	(5,385)
Net cash provided by financing activities	(39,611)	(31,879)	(15,237)
Net change in cash and cash equivalents	(11,829)	2,753	28,353
Beginning cash and cash equivalents	98,996	96,243	67,890
Ending cash and cash equivalents	$ 87,167	$ 98,996	$ 96,243