Securities - Amortized Cost and Fair Value of Debt Securities, by Contractual Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Available-for-sale Securities, Debt Maturities [Abstract]
Amortized Cost, One year or less	$ 12,561
Amortized Cost, After one year through five years	121,400
Amortized Cost, After five years through ten years	46,251
Amortized Cost, After ten years	2,009
Amortized Cost, Total	182,221
Amortized Cost, Mortgage-backed securities	32,382
Amortized Cost	214,603	$ 234,793
Fair Value, One year or less	12,594
Fair Value, After one year through five years	122,422
Fair Value, After five years through ten years	47,068
Fair Value, After ten years	2,268
Fair Value, Total	184,352
Fair Value, Mortgage-backed securities	32,711
Total, Fair Value	$ 217,063	$ 235,115