Loans and Allowance for Loan Losses - Troubled Debt Restructuring Categorized by Loan (Detail) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2016 USD ($) Contract	Dec. 31, 2015 USD ($) Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	3	4
Pre Modification Outstanding Recorded Investment	$ 38	$ 2,017
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 38	$ 2,016
Residential 1-4 Family [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	2	2
Pre Modification Outstanding Recorded Investment	$ 35	$ 77
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 35	$ 77
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	0
Pre Modification Outstanding Recorded Investment	$ 0	$ 0
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 0
Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	0	1
Pre Modification Outstanding Recorded Investment	$ 0	$ 1,938
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 1,938
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	0
Pre Modification Outstanding Recorded Investment	$ 0	$ 0
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 0	$ 0
Agricultural, Installment and Other [Member]
Financing Receivable, Modifications [Line Items]
Number of Contracts \| Contract	1	1
Pre Modification Outstanding Recorded Investment	$ 3	$ 2
Post Modification Outstanding Recorded Investment, Net of Related Allowance	$ 3	$ 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=66008989&loc=SL6953676-111524

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