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Securities - Summary of Amortized Costs and Fair Values of Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total	$ 98,181	$ 105,851
Securities available for sale, Gross Unrealized Gains	1,059	601
Securities available for sale, Gross Unrealized (Losses)	(221)	(893)
Securities available for sale, Fair Value	99,019	105,559	[1]
Securities held to maturity, Amortized Cost	64,963	66,519
Securities held to maturity, Gross Unrealized Gains	662	264
Securities held to maturity, Gross Unrealized (Losses)	(57)	(345)
Securities held to maturity, Fair Value	65,568	66,438	[1]
Total securities, Amortized Cost	163,144	172,370
Total securities, Gross Unrealized Gains	1,721	865
Total securities, Gross Unrealized (Losses)	(278)	(1,238)
Total securities, Fair Value	164,587	171,997
U.S. Agency and Mortgage-Backed Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total	83,151	89,919
Securities available for sale, Gross Unrealized Gains	694	261
Securities available for sale, Gross Unrealized (Losses)	(205)	(843)
Securities available for sale, Fair Value	83,640	89,337
Securities held to maturity, Amortized Cost	48,126	49,662
Securities held to maturity, Gross Unrealized Gains	308	36
Securities held to maturity, Gross Unrealized (Losses)	(53)	(326)
Securities held to maturity, Fair Value	48,381	49,372
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total	15,029	15,931
Securities available for sale, Gross Unrealized Gains	355	333
Securities available for sale, Gross Unrealized (Losses)	(16)	(50)
Securities available for sale, Fair Value	15,368	16,214
Securities held to maturity, Amortized Cost	15,337	15,357
Securities held to maturity, Gross Unrealized Gains	316	228
Securities held to maturity, Gross Unrealized (Losses)	(4)	(19)
Securities held to maturity, Fair Value	15,649	15,566
Corporate Equity Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Debt and Equity, Amortized Cost Basis, Total	1	1
Securities available for sale, Gross Unrealized Gains	10	7
Securities available for sale, Fair Value	11	8
Corporate Debt Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Securities held to maturity, Amortized Cost	1,500	1,500
Securities held to maturity, Gross Unrealized Gains	38
Securities held to maturity, Fair Value	$ 1,538	$ 1,500
[1] Derived from audited consolidated financial statements.

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