DUE TO DEPOSITORS (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits Liability [Abstract]
Savings accounts	$ 362,092	$ 366,921
Certificates of deposit ("CDs")	1,091,887	1,048,465
Money market accounts	2,517,439	2,576,081
Interest bearing checking accounts	124,283	106,525
Non-interest bearing checking accounts	307,746	297,434
Total deposits	$ 4,403,447	$ 4,395,426
Weighted Average Rate Domestic Deposits Liability [Abstract]
Savings accounts	0.07%	0.05%
Certificates of deposit ("CDs")	1.47%	1.47%
Money market accounts	0.96%	0.86%
Interest bearing checking accounts	0.08%	0.08%
Non-interest bearing checking accounts	0.00%	0.00%
TOTAL	0.92%	0.86%
Maturities of Time Deposits [Abstract]
2018	$ 579,781
2019	408,703
2020	65,884
2021	18,818
2022	16,197
2023 and beyond	2,504
TOTAL	$ 1,091,887
Weighted Average Rate of Time Deposits [Abstract]
2018	1.32%
2019	1.58%
2020	1.53%
2021	1.58%
2022	1.64%
2023 and beyond	1.59%
TOTAL	1.44%
Aggregate amount of CDs $250,000 or More	$ 179,307	$ 203,308