Loans - Loan Balances (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Total Loans	$ 1,164,661	$ 1,055,506
Allowance for loan losses	(13,134)	(13,305)
Net loans	1,151,527	1,042,201
Commercial and Agriculture [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	152,473	135,462
Commercial Real Estate Owner Occupied [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	164,099	161,364
Commercial Real Estate Non Owner Occupied [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	425,623	395,931
Residential Real Estate [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	268,735	247,308
Real Estate Construction [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	97,531	56,293
Farm Real Estate [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	39,461	41,170
Consumer and Other [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	$ 16,739	$ 17,978

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount after allowance and 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 and loans held for sale.

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