Investment Securities - Summary of Amortized Cost and Fair Value by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Amortized Cost
Available-for-sale: Due in one year or less	$ 2,682
Available-for-sale: Due after one year through five years	6,265
Available-for-sale: Due after five years through ten years	51,206
Available-for-sale: Due after ten years	297,279
Available-for-sale, Amortized Cost	357,432
Fair Value
Available-for-sale: Due in one year or less	2,688
Available-for-sale: Due after one year through five years	6,430
Available-for-sale: Due after five years through ten years	52,768
Available-for-sale: Due after ten years	293,858
Available-for-sale, Fair Value	355,744
Amortized Cost
Held-to-maturity: Due in one year or less	354
Held-to-maturity: Due after one year through five years	6,535
Held-to-maturity: Due after five years through ten years	31,540
Held-to-maturity: Due after ten years	52,813
Held-to-maturity, Amortized Cost	91,242	$ 98,211
Fair Value
Held-to-maturity: Due in one year or less	354
Held-to-maturity: Due after one year through five years	6,579
Held-to-maturity: Due after five years through ten years	32,064
Held-to-maturity: Due after ten years	52,770
Held-to-maturity, Fair Value	$ 91,767	$ 98,261