Investment Securities (Details 2) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Amortized Cost
Due in one year or less	$ 12,649
Due after one year through five years	255,563
Due after five years through ten years	1,005,595
Due after ten years	2,150,606
Total securities available-for-sale	3,424,413	$ 3,213,655
Fair Value
Due in one year or less	12,997
Due after one year through five years	259,332
Due after five years through ten years	1,013,932
Due after ten years	2,188,299
Total securities available-for-sale	$ 3,474,560	$ 3,223,830