SECURITIES (Debt Securities, Held-to-Maturity, Credit Rating) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	$ 1,015,942	$ 521,355
U.S. Government and agency obligations
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	315	316
Municipal bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	442,328	420,555
Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	3,059	3,092
Mortgage-backed or related securities
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	570,240	97,392
Standard & Poor's, AAA to A Rating
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	446,411	406,863
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	429,085	406,363
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	16,826	0
Standard & Poor's, Not Rated
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	569,531	114,492
Standard & Poor's, Not Rated | U.S. Government and agency obligations
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	315	316
Standard & Poor's, Not Rated | Municipal bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	13,243	14,192
Standard & Poor's, Not Rated | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	2,559	2,592
Standard & Poor's, Not Rated | Mortgage-backed or related securities
Financing Receivable, Credit Quality Indicator [Line Items]
Debt securities, held-to-maturity	$ 553,414	$ 97,392