Investment Securities (Details 3) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Investment Securities, Available-for-Sale, Amortized Cost
Due in one year or less	$ 7,870
Due after one year through five years	278,393
Due after five years through ten years	988,421
Due after ten years	2,413,407
Total	3,688,091	$ 4,017,909
Investment Securities, Available-for-Sale, Estimated Fair Value
Due in one year or less	7,897
Due after one year through five years	283,059
Due after five years through ten years	1,013,054
Due after ten years	2,493,177
Securities available‑for‑sale	$ 3,797,187	$ 4,009,431