Loans and Allowance for Loan Losses - Schedule of Number of Loans Modified Troubled Debt Restructuring by Loan Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
Sep. 30, 2014 SecurityLoan	Dec. 31, 2013 SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Loans	23	40
Pre-Modification Outstanding Principal Balance	$ 5,555	$ 12,025
Post-Modification Principal Balance	4,297	7,666
Subsequent default number of loans	3	6
Recorded Investment	986	1,639
Construction, Land Development and Other Land Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	4	10
Pre-Modification Outstanding Principal Balance	3,282	7,551
Post-Modification Principal Balance	2,373	3,837
Subsequent default number of loans		2
Recorded Investment		566
Secured by 1-4 Family Residential Properties [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	7	17
Pre-Modification Outstanding Principal Balance	426	1,375
Post-Modification Principal Balance	359	1,067
Secured by Non-farm, Non-residential Properties [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	8	9
Pre-Modification Outstanding Principal Balance	1,688	2,683
Post-Modification Principal Balance	1,452	2,418
Subsequent default number of loans	3	4
Recorded Investment	986	1,073
Commercial Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	4	4
Pre-Modification Outstanding Principal Balance	159	416
Post-Modification Principal Balance	$ 113	$ 344

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

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Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

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- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953682-111524

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Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

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