COMMITMENTS AND CONTINGENT LIABILITIES (Commitments to Extend Credit) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) request	Dec. 31, 2019 USD ($) request
Long-term Credit Commitments [Line Items]
Residential mortgage loans, repurchase obligation amount	$ 0	$ 313
Number of repurchase requests | request	0	0
AimBank
Long-term Credit Commitments [Line Items]
Loss holdback	$ 5,300
Commitments to Extend Credit
Long-term Credit Commitments [Line Items]
Commitments to extend credit, amount	3,260,000	$ 2,970,000
Standby Letters of Credit
Long-term Credit Commitments [Line Items]
Commitments to extend credit, amount	$ 73,200	$ 79,500