Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Held-to-maturity, Amortized Cost
Due 3 months or less	$ 165
Due after 3 months through one year	1,083
Due after one year through five years	4,372
Due after five years through ten years	16,554
Due after ten years	68,639
Agency mortgage-backed securities	111,591
Total	202,404	$ 109,311
Held-to-maturity, Estimated Fair Value
Due 3 months or less	165
Due after 3 months through one year	1,087
Due after one year through five years	4,448
Due after five years through ten years	17,451
Due after ten years	70,037
Agency mortgage-backed securities	112,622
Estimated Fair Value	$ 205,810	$ 109,821