Securities - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity - Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Held-to-maturity, Amortized Cost
Due less than 3 months	$ 612
Due after 3 months through one year	1,039
Due after one through five years	5,239
Due after five through ten years	14,726
Due after ten years	70,973
Agency mortgage-backed securities	92,576
Total	185,165	$ 109,311
Held-to-maturity, Estimated Fair Value
Due less than 3 months	614
Due after 3 months through one year	1,045
Due after one through five years	5,319
Due after five through ten years	15,533
Due after ten years	71,711
Agency mortgage-backed securities	92,825
Estimated Fair Value	$ 187,047	$ 109,821