Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Due in one year or less, Amortized Cost	$ 632
Due after one year through five years, Amortized Cost	29,651
Due after five years through ten years,Amortized Cost	30,734
Due after ten years, Amortized Cost	66,054
Mortgage-backed securities, Amortized Cost	65,320
Equity securities, Amortized Cost	481
Amortized Cost	192,872	$ 192,252
Due in one year or less, Fair Value	632
Due after one year through five years, Fair Value	29,782
Due after five years through ten years, Fair Value	32,123
Due after ten years, Fair Value	68,116
Mortgage-backed securities, Fair Value	66,206
Equity securities, Fair Value	570
Total securities available for sale, Fair Value	$ 197,429	$ 197,905