DEPOSITS (Deposit Liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Deposits:
Non-interest-bearing accounts	$ 6,388,815	$ 6,385,177
Interest-bearing checking	1,859,582	1,947,414
Regular savings accounts	2,801,177	2,784,716
Money market accounts	2,406,678	2,370,995
Total interest-bearing transaction and saving accounts	7,067,437	7,103,125
Certificates of deposit less than or equal to $250,000	587,105	657,615
Certificates of deposit greater than $250,000	169,207	181,016
Total certificates of deposit	756,312	838,631
Total deposits	14,212,564	14,326,933
Included in total deposits:
Public fund transaction and savings accounts	400,624	353,874
Public fund interest-bearing certificates	37,415	39,961
Total public deposits	$ 438,039	$ 393,835