PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION, Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Interest expense	$ (15,946)	$ (28,367)
Other expense	(17,818)	(14,592)
Income before income taxes	56,603	36,701
Income tax (benefit)	11,250	7,481
Net income	45,353	29,220
South Plains Financial, Inc. [Member]
Income Statement [Abstract]
Dividends	20,500	10,000
Other income	115	64
ESOP Contribution	0	(1,800)
Interest expense	(3,390)	(3,562)
Other expense	(1,572)	(2,221)
Income before income taxes	15,653	2,481
Income tax (benefit)	(1,018)	(1,498)
Equity in undistributed subsidiary income	28,682	25,241
Net income	$ 45,353	$ 29,220