SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Subsidiaries Information (Details)	3 Months Ended
	Mar. 31, 2026
City Bank [Member] \| Bank Subsidiary [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Wholly-Owned, Consolidated Subsidiaries	Bank subsidiary
Ruidoso Retail, Inc. [Member] \| Non-bank Subsidiary [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Wholly-Owned, Consolidated Subsidiaries	Non-bank subsidiary
CB Provence, LLC [Member] \| Non-bank Subsidiary [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Wholly-Owned, Consolidated Subsidiaries	Non-bank subsidiary
CBT Brushy Creek, LLC [Member] \| Non-bank Subsidiary [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Wholly-Owned, Consolidated Subsidiaries	Non-bank subsidiary
CBT Properties, LLC [Member] \| Non-bank Subsidiary [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Wholly-Owned, Consolidated Subsidiaries	Non-bank subsidiary
South Plains Financial Capital Trusts ("SPFCT") III-V [Member] \| Non-bank Subsidiary [Member]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Wholly-Owned, Equity Method Subsidiaries	Non-bank subsidiaries