DERIVATIVES - Additional Information (Details) $ in Thousands	Sep. 30, 2019 USD ($) entity	Dec. 31, 2018 USD ($) entity
Derivative [Line Items]
Number of counterparties | entity	17	13
Derivative liabilities	$ 148,101	$ 29,188
Derivative, Notional Amount	7,164,776	2,719,980
Other Credit Derivatives [Member]
Derivative [Line Items]
Derivative, Notional Amount	53,000	12,300
Credit Risk Derivative Liabilities, at Fair Value		0
Credit Risk Derivative Assets, at Fair Value	$ (200)
Foreign Exchange [Member]
Derivative [Line Items]
Number of counterparties | entity	4
Credit Risk Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 185,600	138,400
Credit Risk Derivative Liabilities, at Fair Value	300	100
Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Derivative, Notional Amount	53,000	20,800
Accrued interest and other liabilities | Derivative
Derivative [Line Items]
Derivative liabilities	92,100	4,900
Derivative, Notional Amount	1,800,000	$ 1,400,000
Accrued interest and other liabilities | Derivative | Foreign Exchange [Member]
Derivative [Line Items]
Derivative liabilities	7,500
Derivative, Notional Amount	$ 1,800,000