Loans - Analysis of Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	$ 6,112	$ 5,357
Charge Offs	(1,030)	(778)	$ (1,262)
Recoveries	557	298	374
Provision (Credit)	625	1,191
Other Non-interest expense related to unfunded	1	44
Ending Balance	6,265	6,112	5,357
Ending balance: individually evaluated for impairment	330	387
Ending balance: collectively evaluated for impairment	5,935	5,725
Ending balance: loans acquired with deteriorated credit quality	1	2
FINANCING RECEIVABLES:
Ending balance	685,878	621,926
Ending balance: individually evaluated for impairment	2,136	1,843
Ending balance: collectively evaluated for impairment	683,742	620,083
Agricultural Real Estate [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	184	131
Provision (Credit)	27	53
Ending Balance	211	184	131
Ending balance: collectively evaluated for impairment	211	184
FINANCING RECEIVABLES:
Ending balance	58,463	50,895
Ending balance: individually evaluated for impairment	63
Ending balance: collectively evaluated for impairment	58,400	50,895
Agricultural [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	547	326
Recoveries	64	44
Provision (Credit)	(29)	177
Ending Balance	582	547	326
Ending balance: individually evaluated for impairment		25
Ending balance: collectively evaluated for impairment	582	522
FINANCING RECEIVABLES:
Ending balance	82,762	74,611
Ending balance: individually evaluated for impairment		25
Ending balance: collectively evaluated for impairment	82,762	74,586
Commercial And Industrial and Industrial Development Bonds [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	1,421	1,359
Charge Offs	(536)
Recoveries	91	20
Provision (Credit)	253	42
Ending Balance	1,229	1,421	1,359
Ending balance: individually evaluated for impairment	114	204
Ending balance: collectively evaluated for impairment	1,115	1,217
FINANCING RECEIVABLES:
Ending balance	106,689	104,824
Ending balance: individually evaluated for impairment	182	327
Ending balance: collectively evaluated for impairment	106,507	104,497
Unfunded Loan Commitment & Letters of Credit [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	207	163
Other Non-interest expense related to unfunded	1	44
Ending Balance	208	207	163
Ending balance: collectively evaluated for impairment	208	207
Receivables Acquired with Deteriorated Credit Quality [Member]
FINANCING RECEIVABLES:
Ending balance: loans acquired with deteriorated credit quality	507	526
Consumer Real Estate [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	537	257
Charge Offs	(38)	(168)
Recoveries	41	34
Provision (Credit)	(202)	414
Ending Balance	338	537	257
Ending balance: individually evaluated for impairment	64	36
Ending balance: collectively evaluated for impairment	274	501
Ending balance: loans acquired with deteriorated credit quality	1	2
FINANCING RECEIVABLES:
Ending balance	87,947	97,550
Ending balance: individually evaluated for impairment	431	301
Ending balance: collectively evaluated for impairment	87,516	97,249
Consumer Real Estate [Member] \| Receivables Acquired with Deteriorated Credit Quality [Member]
FINANCING RECEIVABLES:
Ending balance: loans acquired with deteriorated credit quality	507	526
Commercial Real Estate [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	2,367	2,107
Charge Offs	(143)	(229)
Recoveries	204	4
Provision (Credit)	88	485
Ending Balance	2,516	2,367	2,107
Ending balance: individually evaluated for impairment	152	111
Ending balance: collectively evaluated for impairment	2,364	2,256
FINANCING RECEIVABLES:
Ending balance	322,230	270,188
Ending balance: individually evaluated for impairment	1,460	1,179
Ending balance: collectively evaluated for impairment	320,770	269,009
Consumer [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	323	292
Charge Offs	(313)	(381)
Recoveries	157	196
Provision (Credit)	170	216
Ending Balance	337	323	292
Ending balance: individually evaluated for impairment		11
Ending balance: collectively evaluated for impairment	337	312
FINANCING RECEIVABLES:
Ending balance	27,787	23,858
Ending balance: individually evaluated for impairment		11
Ending balance: collectively evaluated for impairment	27,787	23,847
Unallocated [Member]
ALLOWANCE FOR CREDIT LOSSES:
Beginning balance	526	722
Provision (Credit)	318	(196)
Ending Balance	844	526	$ 722
Ending balance: collectively evaluated for impairment	$ 844	$ 526

Allowance For Credit Losses [Abstract]

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Financing receivable allowance for credit losses acquired with deteriorated credit quality ending period.

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Financing Receivables [Abstract]

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Other non interest Income expense (recovery) related to unfunded.

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Amount of expense related to estimated loss and recoveries from loan and lease transactions.

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Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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-Publisher FASB
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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services.

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