Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 8,062
Amortized Cost, Due after one year through five years	28,108
Amortized Cost, Due after five years through ten years	32,459
Amortized Cost, Due after ten years	60,208
Amortized Cost, Mortgage-backed securities	65,176
Amortized Cost, Equity securities	481
Amortized Cost	194,494	$ 190,863
Fair value, Due in one year or less	8,071
Fair value, Due after one year through five years	28,431
Fair value, Due after five years through ten years	34,512
Fair value, Due after ten years	63,989
Fair value, Mortgage-backed securities	66,194
Fair value, Equity securities	589
Fair value, Total securities available for sale	$ 201,786	$ 196,249