Allowance for Loan Losses - Schedule of Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016 USD ($) Contract	Sep. 30, 2016 USD ($) Contract	Sep. 30, 2015 USD ($) Contract
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts \| Contract	1	9	1
Pre-Modification Outstanding Recorded Investment	$ 86	$ 1,537	$ 41
Post-Modification Outstanding Recorded Investment	$ 86	$ 1,537	$ 41
Commercial and Agriculture [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts \| Contract		4
Pre-Modification Outstanding Recorded Investment		$ 529
Post-Modification Outstanding Recorded Investment		$ 529
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts \| Contract		2
Pre-Modification Outstanding Recorded Investment		$ 308
Post-Modification Outstanding Recorded Investment		$ 308
Real Estate Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts \| Contract			1
Pre-Modification Outstanding Recorded Investment			$ 41
Post-Modification Outstanding Recorded Investment			$ 41
Farm Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of Contracts \| Contract	1	3
Pre-Modification Outstanding Recorded Investment	$ 86	$ 700
Post-Modification Outstanding Recorded Investment	$ 86	$ 700

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

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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