DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING ACTIVITIES - Offsetting Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Cash Collateral Pledged	$ 17,000	$ 23,450
Net Amount	17,000	23,450
MNA counterparty
Derivative [Line Items]
Cash Collateral Pledged	17,000	23,450
Net Amount	17,000	23,450
Customer loan derivative liability
Derivative [Line Items]
Derivative liabilities	(16,150)	(25,895)
Customer loan derivative liability | MNA counterparty
Derivative [Line Items]
Derivative liabilities	(10,258)	(15,938)
Customer loan derivative liability | RPA counterparty
Derivative [Line Items]
Derivative liabilities	(5,892)	(9,957)
Customer loan derivative asset
Derivative [Line Items]
Derivative Assets	16,150	25,895
Customer loan derivative asset | MNA counterparty
Derivative [Line Items]
Derivative Assets	10,258	15,938
Customer loan derivative asset | RPA counterparty
Derivative [Line Items]
Derivative Assets	$ 5,892	$ 9,957