INVESTMENT SECURITIES (Details 5) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Amortized Cost
Due within one year	$ 664,482
Due after one year through five years	587,483
Due after five years through ten years	362,297
Due after ten years	1,610,545
Total available-for-sale investment securities	3,224,807
Estimated Fair Value
Due within one year	661,989
Due after one year through five years	592,032
Due after five years through ten years	363,709
Due after ten years	1,618,894
Total available-for-sale investment securities	3,236,624	$ 3,773,226
Amortized Cost
Due after ten years	154,461
Estimated Fair Value
Due after ten years	154,296
Fair values of available-for-sale investment securities pledged	$ 955,700	$ 873,000