DEPOSITS (Summary of Certain Deposits) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Non-interest bearing demand deposits	$ 885,622	$ 819,803
Savings and transaction accounts:
Savings deposits	263,570	268,970
Interest bearing demand deposits	3,123,033	2,758,109
Time deposits:
Other time deposits	251,218	238,994
Deposits of $100,000 to $250,000	236,354	212,232
Deposits of $250,000 or more	925,011	712,593
Total deposits	$ 4,008,655	$ 3,577,912