BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Textuals) (Details)	Dec. 31, 2023 banking_location office
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of offices | banking_location	135
Subsidiary, Banner Bank [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Number of production offices | office	13
Minimum [Member] | Core Deposit Intangibles [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Intangible asset, useful life	8 years
Maximum [Member] | Core Deposit Intangibles [Member]
Basis of Presentation and Summary of Significant Accounting Policies [Abstract]
Intangible asset, useful life	10 years