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INVESTMENT SECURITIES - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Investment Securities Pledged as Collateral
Accrued interest and fees receivable	$ 5,400		$ 5,400
Investment securities pledged to collateralize certain deposits and borrowings	2,050,000		2,050,000		$ 2,140,000
Proceeds from sales of securities			$ 30,991	$ 733,789
Percentage of first half of subscription on FRB stock			0.50%
Percentage of remaining half of subscription on FRB stock			0.50%
U.S. Treasury and agency securities
Investment Securities Pledged as Collateral
Book value of available-for-sale		$ 786,100
Gross realized losses		52,300
Proceeds from sales of securities		$ 733,800
U.S. Treasury and agency securities | Securities Sold under Agreements to Repurchase
Investment Securities Pledged as Collateral
Investment securities pledged to collateralize certain deposits and borrowings	344,800		$ 344,800		$ 598,900
Obligations of state and political subdivisions
Investment Securities Pledged as Collateral
Book value of available-for-sale	31,200		$ 31,200
Gross realized gains	200
Gross realized losses	400
Proceeds from sales of securities	$ 31,000

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Book value of investment in debt securities, available-for-sale, sold by the entity.

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For an unclassified balance sheet, the amount of fees and other revenue, excluding investment income receivable, earned but not yet received, which were recognized in conformity with revenue recognition criteria based on estimates or specific contractual terms.

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Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

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Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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