Investment Securities - Investment Securities Available-for-Sale and Held-to-Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale, Amortized Cost	$ 200,699	$ 202,039
Available-for-Sale, Gross Unrealized Gains	2,361	3,306
Available-for-Sale, Gross Unrealized Losses	(813)	(379)
Available-for-Sale, Estimated Fair Value	202,247	204,966
Held-to-Maturity, Amortized Cost	43,929	29,120
Held-to-Maturity, Gross Unrealized Gains	71	88
Held-to-Maturity, Gross Unrealized Losses	(371)	(54)
Held-to-Maturity, Estimated Fair Value	43,629	29,154
Residential [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale, Amortized Cost	138,119	139,980
Available-for-Sale, Gross Unrealized Gains	1,216	1,896
Available-for-Sale, Gross Unrealized Losses	(566)	(192)
Available-for-Sale, Estimated Fair Value	138,769	141,684
Commercial [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale, Amortized Cost	45,144	35,873
Available-for-Sale, Gross Unrealized Gains	237	164
Available-for-Sale, Gross Unrealized Losses	(234)	(93)
Available-for-Sale, Estimated Fair Value	45,147	35,944
Held-to-Maturity, Amortized Cost	17,256	10,666
Held-to-Maturity, Gross Unrealized Gains	48	65
Held-to-Maturity, Gross Unrealized Losses	(130)	(2)
Held-to-Maturity, Estimated Fair Value	17,174	10,729
Obligations of States and Political Subdivisions [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale, Amortized Cost	14,566	15,673
Available-for-Sale, Gross Unrealized Gains	907	1,241
Available-for-Sale, Gross Unrealized Losses	(12)
Available-for-Sale, Estimated Fair Value	15,461	16,914
Held-to-Maturity, Amortized Cost	1,580	584
Held-to-Maturity, Gross Unrealized Gains		4
Held-to-Maturity, Gross Unrealized Losses	(6)
Held-to-Maturity, Estimated Fair Value	1,574	588
Obligations of U.S. Government Sponsored Agencies [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale, Amortized Cost	1,999	6,360
Available-for-Sale, Gross Unrealized Gains	1	5
Available-for-Sale, Gross Unrealized Losses		(1)
Available-for-Sale, Estimated Fair Value	2,000	6,364
Held-to-Maturity, Amortized Cost	25,093	17,870
Held-to-Maturity, Gross Unrealized Gains	23	19
Held-to-Maturity, Gross Unrealized Losses	(235)	(52)
Held-to-Maturity, Estimated Fair Value	24,881	17,837
Corporate notes [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale, Amortized Cost	791
Available-for-Sale, Gross Unrealized Losses	(1)
Available-for-Sale, Estimated Fair Value	790
U.S. Treasury Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale, Amortized Cost	80	4,153
Available-for-Sale, Gross Unrealized Losses		(93)
Available-for-Sale, Estimated Fair Value	$ 80	$ 4,060

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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