Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 9,728
Amortized Cost, Due after one year through five years	27,019
Amortized Cost, Due after five years through ten years	31,857
Amortized Cost, Due after ten years	60,658
Amortized Cost, Mortgage-backed securities	62,016
Amortized Cost, Equity securities	481
Amortized Cost	191,759	$ 190,863
Fair value, Due in one year or less	9,744
Fair value, Due after one year through five years	27,398
Fair value, Due after five years through ten years	34,003
Fair value, Due after ten years	65,651
Fair value, Mortgage-backed securities	63,247
Fair value, Equity securities	600
Fair value, Total securities available for sale	$ 200,643	$ 196,249