PARENT COMPANY ONLY CONDENSED FINANCIAL INFORMATION, Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
ASSETS [Abstract]
Cash and cash equivalents	$ 486,821	$ 300,307
Other assets	26,826	23,384
Total assets	3,901,855	3,599,160	$ 3,237,167
LIABILITIES AND STOCKHOLDERS' EQUITY [Abstract]
Accrued expenses and other liabilities	31,038	31,229
Stockholders' equity	407,427	370,048	$ 306,182	$ 154,580
Total liabilities and stockholders' equity	3,901,855	3,599,160
South Plains Financial, Inc. [Member]
ASSETS [Abstract]
Cash and cash equivalents	96,243	67,890
Other assets	6,013	4,248
Total assets	531,426	493,544
LIABILITIES AND STOCKHOLDERS' EQUITY [Abstract]
Debt	122,168	121,982
Accrued expenses and other liabilities	1,831	1,514
Stockholders' equity	407,427	370,048
Total liabilities and stockholders' equity	531,426	493,544
South Plains Financial, Inc. [Member] | Bank Subsidiary [Member]
ASSETS [Abstract]
Investment in subsidiary	429,119	421,355
South Plains Financial, Inc. [Member] | Other Subsidiary [Member]
ASSETS [Abstract]
Investment in subsidiary	$ 51	$ 51