Investment Securities - Contractual Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less	$ 4,846
Due after one year through three years	37,037
Due after three years through five years	57,565
Due after five years through ten years	246,989
Due after ten years	450,420
Investment securities with no stated maturities	45
Amortized Cost	796,902	$ 807,921
Fair Value
Due in one year or less	4,868
Due after one year through three years	37,528
Due after three years through five years	58,761
Due after five years through ten years	253,375
Due after ten years	461,316
Investment securities with no stated maturities	72
Fair Value	$ 815,920	$ 811,869