Investment Securities (Details 2) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Amortized Cost
Due in one year or less	$ 14,660
Due after one year through five years	194,493
Due after five years through ten years	1,028,156
Due after ten years	2,467,959
Total securities available-for-sale	3,705,268	$ 4,017,909
Fair Value
Due in one year or less	14,647
Due after one year through five years	197,141
Due after five years through ten years	1,054,251
Due after ten years	2,541,205
Total securities available-for-sale	$ 3,807,244	$ 4,009,431