PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION, Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
ESOP Contribution	$ (1,800)	$ (2,000)
Interest expense	(28,367)	(22,482)
Other expense	(14,592)	(13,981)
Income before income taxes	36,701	25,389
Income tax (benefit)	7,481	(3,901)
Net income	29,220	29,290
South Plains Financial, Inc. [Member]
Income Statement [Abstract]
Dividends	10,000	17,500
Other income	64	60
ESOP Contribution	(1,800)	(2,000)
Interest expense	(3,562)	(2,870)
Other expense	(2,221)	(1,001)
Income before income taxes	2,481	11,689
Income tax (benefit)	(1,498)	(800)
Equity in undistributed subsidiary income	25,241	16,801
Net income	$ 29,220	$ 29,290