Allowance for Loan Losses - Allowance by Impairment Methodology and Loans by Impairment Methodology (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Allowance for loan losses:
Beginning Balance			$ 6,718	$ 10,644	$ 10,644
Charge-offs			(783)	(545)	(927)
Recoveries			294	507	851
Provision for (recovery of) loan losses	$ (100)	$ (400)	(100)	(600)	(3,850)
Ending Balance	6,129	10,006	6,129	10,006	6,718
Ending Balance:
Allowance for loan losses, Individually evaluated for impairment	1,563	1,873	1,563	1,873	1,907
Allowance for loan losses, Collectively evaluated for impairment	4,566	8,133	4,566	8,133	4,811
Loans:
Ending Balance	391,721	367,490	391,721	367,490	378,410
Loans, Individually evaluated for impairment	10,770	19,882	10,770	19,882	13,922
Loans, Collectively evaluated for impairment	380,951	347,608	380,951	347,608	364,488
Construction and Land Development [Member]
Allowance for loan losses:
Beginning Balance			1,403	2,710	2,710
Charge-offs					(91)
Recoveries			2	40	80
Provision for (recovery of) loan losses			204	(636)	(1,296)
Ending Balance	1,609	2,114	1,609	2,114	1,403
Ending Balance:
Allowance for loan losses, Individually evaluated for impairment	437	779	437	779	245
Allowance for loan losses, Collectively evaluated for impairment	1,172	1,335	1,172	1,335	1,158
Loans:
Ending Balance	32,009	32,795	32,009	32,795	29,475
Loans, Individually evaluated for impairment	3,319	6,427	3,319	6,427	3,205
Loans, Collectively evaluated for impairment	28,690	26,368	28,690	26,368	26,270
Secured by 1-4 Family Residential [Member]
Allowance for loan losses:
Beginning Balance			1,204	2,975	2,975
Charge-offs			(47)	(104)	(272)
Recoveries			83	7	15
Provision for (recovery of) loan losses			(314)	18	(1,514)
Ending Balance	926	2,896	926	2,896	1,204
Ending Balance:
Allowance for loan losses, Individually evaluated for impairment	79	126	79	126	173
Allowance for loan losses, Collectively evaluated for impairment	847	2,770	847	2,770	1,031
Loans:
Ending Balance	173,265	151,043	173,265	151,043	163,727
Loans, Individually evaluated for impairment	2,387	3,297	2,387	3,297	3,414
Loans, Collectively evaluated for impairment	170,878	147,746	170,878	147,746	160,313
Other Real Estate [Member]
Allowance for loan losses:
Beginning Balance			3,658	4,418	4,418
Charge-offs			(471)	(203)	(203)
Recoveries			1	339	509
Provision for (recovery of) loan losses			(16)	(167)	(1,066)
Ending Balance	3,172	4,387	3,172	4,387	3,658
Ending Balance:
Allowance for loan losses, Individually evaluated for impairment	1,025	911	1,025	911	1,456
Allowance for loan losses, Collectively evaluated for impairment	2,147	3,476	2,147	3,476	2,202
Loans:
Ending Balance	155,396	146,483	155,396	146,483	151,802
Loans, Individually evaluated for impairment	4,944	9,994	4,944	9,994	7,183
Loans, Collectively evaluated for impairment	150,452	136,489	150,452	136,489	144,619
Commercial and Industrial [Member]
Allowance for loan losses:
Beginning Balance			310	442	442
Charge-offs			(59)	(36)	(43)
Recoveries			62	3	18
Provision for (recovery of) loan losses			(55)	65	(107)
Ending Balance	258	474	258	474	310
Ending Balance:
Allowance for loan losses, Individually evaluated for impairment	22	57	22	57	33
Allowance for loan losses, Collectively evaluated for impairment	236	417	236	417	277
Loans:
Ending Balance	19,319	24,797	19,319	24,797	21,166
Loans, Individually evaluated for impairment	120	164	120	164	120
Loans, Collectively evaluated for impairment	19,199	24,633	19,199	24,633	21,046
Consumer and Other Loans [Member]
Allowance for loan losses:
Beginning Balance			143	99	99
Charge-offs			(206)	(202)	(318)
Recoveries			146	118	229
Provision for (recovery of) loan losses			81	120	133
Ending Balance	164	135	164	135	143
Ending Balance:
Allowance for loan losses, Collectively evaluated for impairment	164	135	164	135	143
Loans:
Ending Balance	11,732	12,372	11,732	12,372	12,240
Loans, Collectively evaluated for impairment	$ 11,732	$ 12,372	$ 11,732	$ 12,372	$ 12,240

Financing receivable loans and leases receivable.

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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