SECURITIES (Debt Securities, Held-to-Maturity, Credit Rating) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	$ 1,082,505	$ 1,117,967
Credit Rating, Not Credit Rated
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	583,991	608,681
U.S. Government and agency obligations
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	308	312
U.S. Government and agency obligations | Credit Rating, Not Credit Rated
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	308	312
Municipal bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	491,152	503,117
Municipal bonds | Credit Rating, Not Credit Rated
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	9,656	11,012
Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	2,813	2,961
Corporate bonds | Credit Rating, Not Credit Rated
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	2,313	2,461
Mortgage-backed or related securities
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	588,232	611,577
Mortgage-backed or related securities | Credit Rating, Not Credit Rated
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	571,714	594,896
Standard & Poor's, AAA to A Rating
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	498,514	509,286
Standard & Poor's, AAA to A Rating | U.S. Government and agency obligations
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	0	0
Standard & Poor's, AAA to A Rating | Municipal bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	481,496	492,105
Standard & Poor's, AAA to A Rating | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	500	500
Standard & Poor's, AAA to A Rating | Mortgage-backed or related securities
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	$ 16,518	$ 16,681