Securities - Aggregate Amortized Costs and Fair Values of Available-for-Sale Securities Portfolio (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 51,769	$ 53,924
Gross Unrealized Gains	871	382
Gross Unrealized (Losses)	(77)	(216)
Fair Value	52,563	54,090	[1]
US Government Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	25,461	21,375
Gross Unrealized Gains	272	69
Gross Unrealized (Losses)	(56)	(156)
Fair Value	25,677	21,288
State and Municipal Obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	19,363	28,599
Gross Unrealized Gains	541	313
Gross Unrealized (Losses)	(21)	(55)
Fair Value	19,883	28,857
Corporate Bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,945	3,950
Gross Unrealized Gains	58
Gross Unrealized (Losses)		(5)
Fair Value	$ 7,003	$ 3,945

[1] Derived from Audited December 31, 2015 Financial Statements