COMMITMENTS AND CONTINGENCIES (Balances of Commitments and Contingencies) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Commitments with off-balance sheet risk:
Total commitments with off-balance sheet risk	$ 5,130,868	$ 4,900,930
Commitments to Extend Credit
Commitments with off-balance sheet risk:
Total commitments with off-balance sheet risk	4,968,910	4,691,272
Standby Letters of Credit
Commitments with off-balance sheet risk:
Total commitments with off-balance sheet risk	$ 161,958	$ 209,658