DERIVATIVES - Additional Information (Details) $ in Thousands	Sep. 30, 2021 USD ($) entity	Dec. 31, 2020 USD ($) entity
Derivative [Line Items]
Number of counterparties | entity	6	20
Derivative liabilities	$ 240,086	$ 272,606
Derivative, Notional Amount	$ 18,498,760	$ 11,875,690
Foreign Exchange
Derivative [Line Items]
Number of counterparties | entity	4	6
Credit Risk Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 321,600	$ 242,400
Credit Risk Derivative Liabilities, at Fair Value	200	300
Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Derivative, Notional Amount	83,200	114,200
Other Credit Derivatives [Member]
Derivative [Line Items]
Derivative, Notional Amount	92,500	112,600
Credit Risk Derivative Assets, at Fair Value	(2,800)	(2,700)
Accrued interest and other liabilities | Derivative
Derivative [Line Items]
Derivative liabilities	100,400	182,300
Derivative, Notional Amount	2,300,000	2,300,000
Accrued interest and other liabilities | Derivative | Foreign Exchange
Derivative [Line Items]
Derivative liabilities	14,900	33,100
Derivative, Notional Amount	$ 6,900,000	$ 3,600,000