Loans and Allowance for Loan Losses - Schedule of Carrying Amount of Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Carrying Amount	$ 7,540	$ 8,387
Impaired loans with no related allowance recorded, Unpaid Principal Balance	7,540	8,778
Impaired loans with no related allowance recorded, Related Allowances	841	762
Impaired loans with an allowance recorded, Carrying Amount	1,889	2,218
Impaired loans with an allowance recorded, Unpaid Principal Balance	1,889	2,218
Total impaired loans, Carrying Amount	9,429	10,605
Total impaired loans, Unpaid Principal Balance	9,429	10,996
Real Estate [Member] \| Construction, Land Development and Other Land Loans [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Carrying Amount	1,445	1,445
Impaired loans with no related allowance recorded, Unpaid Principal Balance	1,445	1,445
Impaired loans with no related allowance recorded, Related Allowances		71
Impaired loans with an allowance recorded, Carrying Amount		603
Impaired loans with an allowance recorded, Unpaid Principal Balance		603
Total impaired loans, Carrying Amount	1,445	2,048
Total impaired loans, Unpaid Principal Balance	1,445	2,048
Real Estate [Member] \| Secured by 1-4 Family Residential Properties [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Carrying Amount	96	96
Impaired loans with no related allowance recorded, Unpaid Principal Balance	96	96
Total impaired loans, Carrying Amount	96	96
Total impaired loans, Unpaid Principal Balance	96	96
Real Estate [Member] \| Secured by Multi-family Residential Properties [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Carrying Amount	752	755
Impaired loans with no related allowance recorded, Unpaid Principal Balance	752	1,146
Impaired loans with no related allowance recorded, Related Allowances	841	691
Impaired loans with an allowance recorded, Carrying Amount	1,889	1,615
Impaired loans with an allowance recorded, Unpaid Principal Balance	1,889	1,615
Total impaired loans, Carrying Amount	2,641	2,370
Total impaired loans, Unpaid Principal Balance	2,641	2,761
Real Estate [Member] \| Secured by Non-farm, Non-residential Properties [Member]
Financing Receivable Impaired [Line Items]
Impaired loans with no related allowance recorded, Carrying Amount	5,247	6,091
Impaired loans with no related allowance recorded, Unpaid Principal Balance	5,247	6,091
Total impaired loans, Carrying Amount	5,247	6,091
Total impaired loans, Unpaid Principal Balance	$ 5,247	$ 6,091

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953550-111524

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Amount of allowance for credit losses related to recorded investment.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

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-Section 50

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

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Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

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Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

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-Section 50

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (a)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5212-111524

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