The useful life of the loan receivable.

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The period of time when the final, large payment is due on a real estate loan.

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The ratio used to analyze the amount of debt that can be supported by the cash flow generated from the property. The calculation is the net income generated by the property divided by the commercial mortgage payment.

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The amount of the mortgage loan as a percentage of the total appraised value of the real property. Loan-to-value is one of the key risk factors that lenders assess when qualifying borrowers for a mortgage.

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Specifies the time period covered by the loan receivable.

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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 held-for-sale and loans and leases covered under loss sharing agreements.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The increase (decrease) during the reporting period of the sum of amounts due within one year (or one business cycle) from customers for the credit sale of goods and services; and from note holders for outstanding loans.

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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.

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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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The face amount of loans that will be sold to other entities.

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Amount, after allowance for bad debt, of loan receivables held-for-sale that are not part of a disposal group. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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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. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

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Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

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Loans and Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 1,946,114	$ 1,836,251
Loans Receivable Held-for-sale, Amount	1,025	1,175
loans and leases receivable gross excluding loans held for sale	1,945,089	1,835,076
Net deferred loan fees, premiums and discounts	(6,613)	(10,259)
Allowance for loan losses	19,977	16,753	$ 14,576	$ 13,682
Net loans	1,918,499	1,808,064
Loans held for sale	1,025	1,175
Increase (Decrease) in Accounts and Notes Receivable	110,400
Loans Receivable, Net	1,939,501	1,825,992
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	107,721	49,366
Loans Receivable, Net	107,594	49,104
Farm loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	127,232	126,216
Loans Receivable, Net	127,183	126,108
1-4 Family residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	294,483	328,119
Loans Receivable, Net	293,667	326,415
Multifamily residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	61,966	83,478
Loans Receivable, Net	61,798	83,200
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	684,639	633,694
Loans Receivable, Net	$ 681,757	630,135
Debt coverage ratio	1.20x
Amortization period of loans	twenty years
Commercial real estate \| Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan To Value Ratio	65.00%
Commercial real estate \| Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan To Value Ratio	80.00%
Loans secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 1,276,041	1,220,873
Loans Receivable, Net	1,271,999	1,214,962
Agricultural loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	86,602	86,735
Loans Receivable, Net	86,631	86,685
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	445,378	412,637
Loans Receivable, Net	$ 444,263	409,033
Loan To Value Ratio	80.00%
Amortization period of loans	seven years
Loans Receivable, Time Period	one year
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 30,070	38,404
Allowance for loan losses	803	693	642	386
Loans Receivable, Net	29,749	38,028
All other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	108,023	77,602
Loans Receivable, Net	106,859	77,284
Agricultural and Farm Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	213,834	212,800
Increase (Decrease) in Accounts and Notes Receivable	$ 1,034
Loan To Value Ratio	65.00%
Amortization period of loans	twenty five years
Loans Receivable, Time Period	one year
Other Grain Farming [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 170,800	171,336
Increase (Decrease) in Accounts and Notes Receivable	(500)
Motels and Hotels Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	131,702
Non-residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	185,967
Residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	131,756
Other Gambling Industries [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	95,713
Commercial/Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	16,546	12,901	11,379	10,914
Agriculture/Agricultural Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	1,742	2,249	1,337	1,360
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 886	874	994	790
Loan To Value Ratio	80.00%
Amortization period of loans	twenty five years
Balloon period	five years
Unallocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 0	$ 36	$ 224	$ 232