DISCLOSURES ABOUT FAIR VALUE OF ASSETS AND LIABILITIES - Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Assets:
Investment securities available for sale	$ 1,983,972	$ 2,344,551
Investment securities held to maturity	1,867,088	2,202,503
Loans held for sale	25,394	11,187
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and due from banks	119,532	167,146
Interest-bearing deposits	179,593	474,154
Investment securities available for sale	2,067	999
Investment securities held to maturity	0	0
Loans held for sale	0	0
Loans, net	0	0
Federal Home Loan Bank stock	0	0
Derivative assets	0	0
Interest receivable	0	0
Liabilities:
Deposits	13,589,440	12,038,992
Borrowings:
Federal funds purchased	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank advances	0	0
Subordinated debentures and other borrowings	0	0
Derivative liabilities	0	0
Interest payable	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Investment securities available for sale	1,976,398	2,338,061
Investment securities held to maturity	1,856,729	2,188,600
Loans held for sale	25,394	11,187
Loans, net	0	0
Federal Home Loan Bank stock	38,056	28,736
Derivative assets	99,086	41,133
Interest receivable	71,605	57,187
Liabilities:
Deposits	820,943	690,089
Borrowings:
Federal funds purchased	185,000
Securities sold under repurchase agreements	194,468	181,572
Federal Home Loan Bank advances	634,399	337,005
Subordinated debentures and other borrowings	138,407	107,892
Derivative liabilities	98,809	41,968
Interest payable	4,971	2,762
Significant Unobservable Inputs (Level 3)
Assets:
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Investment securities available for sale	5,507	5,491
Investment securities held to maturity	10,359	13,903
Loans held for sale	0	0
Loans, net	10,899,928	9,068,319
Federal Home Loan Bank stock	0	0
Derivative assets	0	0
Interest receivable	0	0
Liabilities:
Deposits	0	0
Borrowings:
Federal funds purchased	0
Securities sold under repurchase agreements	0	0
Federal Home Loan Bank advances	0	0
Subordinated debentures and other borrowings	0	0
Derivative liabilities	0	0
Interest payable	0	0
Carrying Amount
Assets:
Cash and due from banks	119,532	167,146
Interest-bearing deposits	179,593	474,154
Investment securities available for sale	1,983,972	2,344,551
Investment securities held to maturity	2,310,796	2,179,802
Loans held for sale	25,394	11,187
Loans, net	11,423,300	9,046,464
Federal Home Loan Bank stock	38,056	28,736
Derivative assets	99,086	41,133
Interest receivable	71,605	57,187
Liabilities:
Deposits	14,434,825	12,732,577
Borrowings:
Federal funds purchased	185,000
Securities sold under repurchase agreements	194,482	181,577
Federal Home Loan Bank advances	643,769	334,055
Subordinated debentures and other borrowings	151,301	118,618
Derivative liabilities	98,809	41,968
Interest payable	$ 4,971	$ 2,762

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