Loans and Allowance for Loan Losses - Troubled Debt Restructuring Categorized by Loan (Detail) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2015 USD ($) Contract	Dec. 31, 2014 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	2	10
Pre Modification Outstanding Recorded Investment	$ 58	$ 2,370
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 58	$ 2,242
Residential 1-4 Family [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	1	6
Pre Modification Outstanding Recorded Investment	$ 56	$ 1,346
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 56	$ 1,218
Multifamily [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	0
Pre Modification Outstanding Recorded Investment	$ 0	$ 0
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 0
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	2
Pre Modification Outstanding Recorded Investment	$ 0	$ 1,020
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 1,020
Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	0
Pre Modification Outstanding Recorded Investment	$ 0	$ 0
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 0
Farmland [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	0
Pre Modification Outstanding Recorded Investment	$ 0	$ 0
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 0
Second Mortgages [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	0
Pre Modification Outstanding Recorded Investment	$ 0	$ 0
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 0
Equity Lines of Credit [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	0
Pre Modification Outstanding Recorded Investment	$ 0	$ 0
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 0
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	1
Pre Modification Outstanding Recorded Investment	$ 0	$ 3
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 3
Agricultural, Installment and Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	1	1
Pre Modification Outstanding Recorded Investment	$ 2	$ 1
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 2	$ 1

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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=49124121&loc=SL6953676-111524

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