DERIVATIVE FINANCIAL INSTRUMENTS - Fair Value of Derivative Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Notional	$ 780,521	$ 801,542
Total derivatives	(15,344)	(17,809)
Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional		113,177
Derivative Liability		(24,039)
Interest rate products | Other assets | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	58,287	61,326
Derivative Asset	3,464	5,369
Interest rate products | Other liabilities | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	58,287	61,326
Derivative Liability	(3,702)	(5,851)
Risk participation agreements | Other liabilities | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	4,333	4,372
Derivative Liability	(6)	(10)
Interest rate lock commitments with customers | Other assets | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	253,235	244,037
Derivative Asset	4,889	8,496
Interest rate lock commitments with customers | Other liabilities | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	14,433	8,413
Derivative Liability	(144)	(117)
Forward sale commitments | Other assets | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	259,014	50,705
Derivative Asset	3,086	583
Forward sale commitments | Other liabilities | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	19,755	258,186
Derivative Liability	(60)	$ (2,240)
Financial derivatives related to sales of certain Visa Class B shares | Other liabilities | Derivatives not designated as hedging instruments
Derivative [Line Items]
Notional	113,177
Derivative Liability	$ (22,871)