FAIR VALUE MEASURES - Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Financial assets:
Cash and due from banks	$ 253,289	$ 244,980
Interest-bearing deposits in banks	1,039,111	975,397
Debt securities held-to-maturity	154,859	144,028
Financial liabilities:
Other borrowings	276,744	291,788
Subordinated deferrable interest debentures	132,807	132,309
Carrying Amount
Financial assets:
Cash and due from banks	253,289	244,980
Interest-bearing deposits in banks	1,039,111	975,397
Debt securities held-to-maturity	173,757	164,677
Loans, net	20,319,309	20,356,125
Financial liabilities:
Deposits	21,912,409	21,722,448
Other borrowings	276,744	291,788
Subordinated deferrable interest debentures	132,807	132,309
Fair Value
Financial assets:
Cash and due from banks	253,289	244,980
Interest-bearing deposits in banks	1,039,111	975,397
Debt securities held-to-maturity	154,859	144,028
Loans, net	19,900,724	19,882,553
Financial liabilities:
Deposits	21,911,054	21,721,421
Other borrowings	272,495	291,213
Subordinated deferrable interest debentures	141,372	142,202
Fair Value | Level 1
Financial assets:
Cash and due from banks	253,289	244,980
Interest-bearing deposits in banks	1,039,111	975,397
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	154,859	144,028
Loans, net	0	0
Financial liabilities:
Deposits	21,911,054	21,721,421
Other borrowings	272,495	291,213
Subordinated deferrable interest debentures	141,372	142,202
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	19,900,724	19,882,553
Financial liabilities:
Deposits	0	0
Other borrowings	0	0
Subordinated deferrable interest debentures	$ 0	$ 0