Securities - Aggregate Amortized Costs and Fair Values of Available-for-Sale Securities Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 42,536	$ 39,721
Gross Unrealized Gains	267	129
Gross Unrealized (Losses)	(199)	(1,328)
Fair Value	42,604us-gaap_AvailableForSaleSecurities	38,522us-gaap_AvailableForSaleSecurities
Certificates of Deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,232	1,736
Gross Unrealized Gains	8	9
Gross Unrealized (Losses)	(2)
Fair Value	2,238	1,745
US Government Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	16,969	9,383
Gross Unrealized Gains	33	11
Gross Unrealized (Losses)	(37)	(86)
Fair Value	16,965	9,308
State and Municipal Obligations
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,335	27,690
Gross Unrealized Gains	226	109
Gross Unrealized (Losses)	(160)	(1,242)
Fair Value	23,401	26,557
Auction Rate Security
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		912
Fair Value		$ 912

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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This item represents the cost of debt and equity 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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