Investment Securities - Contractual Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Amortized Cost
Due in one year or less	$ 5,612
Due after one year through five years	110,610
Due after five years through ten years	248,162
Due after ten years	423,752
Investment securities with no stated maturities	45
Amortized Cost	788,181	$ 798,639
Fair Value
Due in one year or less	5,653
Due after one year through five years	111,912
Due after five years through ten years	248,257
Due after ten years	424,644
Investment securities with no stated maturities	128
Fair Value	$ 790,594	$ 794,645