Parent Company Only Financial Statements - Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows from Operating Activities
Net income	$ 7,631us-gaap_NetIncomeLoss	$ 9,874us-gaap_NetIncomeLoss	$ 2,800us-gaap_NetIncomeLoss
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Gain on sale of securities available for sale	(696)us-gaap_GainLossOnSaleOfSecuritiesNet		(1,285)us-gaap_GainLossOnSaleOfSecuritiesNet
(Increase) decrease in other assets	(620)	143	3,620
Decrease in other liabilities	372	660	705
Cash Flows from Investing Activities
Proceeds from sale of securities available for sale	21,342	1,850	26,158
Net cash provided by (used in) investing activities	55	8,787	(2,278)
Cash Flows from Financing Activities
Cash dividends paid on common stock, net of reinvestment	(342)us-gaap_PaymentsOfDividendsCommonStock
Cash dividends paid on preferred stock	(1,035)	(758)	(758)
Net proceeds from issuance of common stock			7,601
Increase (decrease) in cash and cash equivalents	(6,663)	480	1,504
Cash and Cash Equivalents
Cash and cash equivalents, beginning of year	31,508	31,028	29,524
Cash and cash equivalents, end of year	24,845	31,508	31,028
Parent Company [Member]
Cash Flows from Operating Activities
Net income	7,631	9,874	2,800
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in undistributed income of subsidiary	(8,012)	(10,156)	(2,342)
Gain on sale of securities available for sale			(139)
(Increase) decrease in other assets	(216)	29	(42)
Decrease in other liabilities			(2)
Net cash provided by (used in) operating activities	(597)	(253)	275
Cash Flows from Investing Activities
Proceeds from sale of securities available for sale			164
Distribution of capital to subsidiary	(1,000)		(1,000)
Net cash provided by (used in) investing activities	(1,000)		(836)
Cash Flows from Financing Activities
Cash dividends paid on common stock, net of reinvestment	(342)
Cash dividends paid on preferred stock	(1,035)	(758)	(758)
Net proceeds from issuance of common stock			7,601
Net cash provided by (used in) financing activities	(1,377)	(758)	6,843
Increase (decrease) in cash and cash equivalents	(2,974)	(1,011)	6,282
Cash and Cash Equivalents
Cash and cash equivalents, beginning of year	5,395	6,406	124
Cash and cash equivalents, end of year	$ 2,421	$ 5,395	$ 6,406

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