FAIR VALUE - Unobservable Inputs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Corporate Bonds and Notes
Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance of recurring Level 3 assets at beginning of period	$ 0	$ 0
Derivative instruments entered into	0	0
Included in earnings - other non-interest income	0	0
Included in other comprehensive income	0	0
Transfers out of Level 3	0	0
Balance of recurring Level 3 assets at end of period	0	0
Derivative Liabilities
Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance of recurring Level 3 assets at beginning of period	(140)	(75)
Derivative instruments entered into	(24)	0
Included in earnings - other non-interest income	(66)	25
Included in other comprehensive income	0	0
Transfers out of Level 3	0	0
Balance of recurring Level 3 assets at end of period	$ (230)	$ (50)