BORROWINGS Borrowings - - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021	Apr. 01, 2018
Carrying Value of Securities Sold under Repurchase Agreements and Deposits Received for Securities Loaned	$ 0	$ 51,300
Federal Funds Purchased	0	0
FHLB short-term borrowings	896,000	225,000
Line of Credit Facility, Maximum Borrowing Capacity	40,000
Short-term Debt	896,000	296,203
Long-term Debt	358,578	409,832
Convertible Subordinated Debt	$ 150,000
Subordinated Borrowing, Interest Rate	5.13%
Debt Instrument, Basis Spread on Variable Rate	5.09%
Subordinated debt	$ 120,000
Subordinated debt	$ 313,476	$ 313,248
Debt, Weighted Average Interest Rate	5.07%	4.86%
Weighted average rate on other long-term debt	0.00%	0.00%
Short-term Debt
Short-term Debt	$ 0	$ 20,000
Long-term Debt [Member]
Subordinated Borrowing, Interest Rate	5.25%
Subordinated Debt [Member]
Subordinated debt	$ 43,500	$ 43,200	$ 49,500
Debt Instrument Maturity Period	30 years
DebtInstrumentMinimumCallablePeriod	5 years