Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Held-to-maturity, Amortized Cost
Due 3 months or less	$ 498
Due after 3 months through one year	503
Due after one through five years	4,721
Due after five through ten years	14,970
Due after ten years	70,699
Agency mortgage-backed securities	118,779
Total	210,170	$ 109,311
Held-to-maturity, Estimated Fair Value
Due 3 months or less	499
Due after 3 months through one year	506
Due after one through five years	4,815
Due after five through ten years	15,941
Due after ten years	72,831
Agency mortgage-backed securities	120,032
Estimated Fair Value	$ 214,624	$ 109,821