INVESTMENT SECURITIES (Details 5) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Amortized Cost
Due within one year	$ 854,642
Due after one year through five years	625,607
Due after five years through ten years	350,091
Due after ten years	1,389,708
Total available-for-sale investment securities	3,220,048
Estimated Fair Value
Due within one year	854,787
Due after one year through five years	633,105
Due after five years through ten years	352,152
Due after ten years	1,400,288
Total available-for-sale investment securities	3,240,332	$ 3,773,226
Amortized Cost
Due after ten years	159,208
Estimated Fair Value
Due after ten years	158,279
Fair value of available-for-sale investment securities pledged	$ 1,060,000	$ 873,000