FAIR VALUE MEASURES - Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Financial assets:
Cash and due from banks	$ 231,515	$ 230,470
Interest-bearing deposits in banks	1,127,641	936,834
Debt securities held-to-maturity	145,714	122,731
Financial liabilities:
Other borrowings	346,446	509,586
Subordinated deferrable interest debentures	131,811	130,315
Carrying Amount
Financial assets:
Cash and due from banks	231,515	230,470
Interest-bearing deposits in banks	1,127,641	936,834
Debt securities held-to-maturity	161,220	141,512
Loans, net	20,584,992	19,925,225
Financial liabilities:
Deposits	21,879,265	20,708,509
Other borrowings	346,446	509,586
Subordinated deferrable interest debentures	131,811	130,315
Fair Value
Financial assets:
Cash and due from banks	231,515	230,470
Interest-bearing deposits in banks	1,127,641	936,834
Debt securities held-to-maturity	145,714	122,731
Loans, net	20,091,402	19,332,899
Financial liabilities:
Deposits	21,876,260	20,707,463
Other borrowings	339,973	501,723
Subordinated deferrable interest debentures	144,819	141,407
Fair Value | Level 1
Financial assets:
Cash and due from banks	231,515	230,470
Interest-bearing deposits in banks	1,127,641	936,834
Debt securities held-to-maturity	0	0
Loans, net	0	0
Financial liabilities:
Deposits	0	0
Other borrowings	0	0
Subordinated deferrable interest debentures	0	0
Fair Value | Level 2
Financial assets:
Cash and due from banks	0	0
Interest-bearing deposits in banks	0	0
Debt securities held-to-maturity	145,714	122,731
Loans, net	0	0
Financial liabilities:
Deposits	21,876,260	20,707,463
Other borrowings	339,973	501,723
Subordinated deferrable interest debentures	144,819	141,407
Fair Value | Level 3
Financial assets:
Cash and due from banks	0	0
Interest-bearing deposits in banks	0	0
Debt securities held-to-maturity	0	0
Loans, net	20,091,402	19,332,899
Financial liabilities:
Deposits	0	0
Other borrowings	0	0
Subordinated deferrable interest debentures	$ 0	$ 0