Hills Bancorporation (HBIA) 10-Q 5 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	HILLS BANCORPORATION
Entity Central Index Key	732,417
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Smaller Reporting Company	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding (in shares)		9,341,956
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Cash and cash equivalents	$ 192,723	$ 154,353
Investment securities available for sale at fair value (amortized cost September 30, 2018 $297,292 December 31, 2017 $286,296)	292,302	285,155
Stock of Federal Home Loan Bank	12,172	15,005
Loans held for sale	3,403	5,162
Loans, net of allowance for loan losses (September 30, 2018 $31,010; December 31, 2017 $29,400)	2,525,720	2,431,165
Property and equipment, net	37,482	37,857
Tax credit real estate investment	9,164	10,076
Accrued interest receivable	12,710	10,772
Deferred income taxes, net	9,675	8,806
Goodwill	2,500	2,500
Other assets	4,632	2,509
Total Assets	3,102,483	2,963,360
Liabilities
Noninterest-bearing deposits	374,927	363,817
Interest-bearing deposits	2,113,825	1,924,748
Total deposits	2,488,752	2,288,565
Federal Home Loan Bank borrowings	215,000	295,000
Accrued interest payable	1,708	1,290
Other liabilities	19,446	23,481
Total Liabilities	2,724,906	2,608,336
Redeemable Common Stock Held by Employee Stock Ownership Plan (ESOP)	47,593	43,308
STOCKHOLDERS' EQUITY
Common stock, no par value; authorized 20,000,000 shares; issued September 30, 2018 10,323,468 shares; December 31, 2017 10,320,315 shares	0	0
Paid in capital	52,223	48,930
Retained earnings	366,053	341,558
Accumulated other comprehensive loss	(4,444)	(2,446)
Treasury stock at cost (September 30, 2018 988,145 shares; December 31, 2017 985,161 shares)	(36,255)	(33,018)
Total Stockholders' Equity	377,577	355,024
Less maximum cash obligation related to ESOP shares	47,593	43,308
Total Stockholders' Equity Less Maximum Cash Obligation Related to ESOP Shares	329,984	311,716
Total Liabilities & Stockholders' Equity	$ 3,102,483	$ 2,963,360

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Amortized Cost	$ 297,292	$ 286,296
Loans, allowance for loan losses	$ 31,010	$ 29,400
STOCKHOLDERS' EQUITY
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, authorized (in shares)	20,000,000	20,000,000
Common stock, issued (in shares)	10,323,468	10,320,315
Treasury stock at cost (in shares)	988,145	985,161

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Interest income:
Loans, including fees	$ 28,280	$ 25,643	$ 81,276	$ 74,378
Investment securities:
Taxable	758	437	2,003	1,237
Nontaxable	862	783	2,617	2,425
Federal funds sold	511	9	1,610	145
Total interest income	30,411	26,872	87,506	78,185
Interest expense:
Deposits	5,284	2,319	13,688	6,730
Short-term borrowings	0	100	0	149
FHLB borrowings	1,607	2,233	5,182	5,938
Total interest expense	6,891	4,652	18,870	12,817
Net interest income	23,520	22,220	68,636	65,368
Provision for loan losses	1,593	130	1,539	1,827
Net interest income after provision for loan losses	21,927	22,090	67,097	63,541
Noninterest income:
Net gain on sale of loans	453	423	1,227	1,119
Other noninterest income	1,271	405	2,075	1,688
Noninterest income	6,668	5,005	18,530	15,247
Noninterest expenses:
Salaries and employee benefits	8,611	8,134	25,718	24,707
Occupancy	1,208	1,087	3,331	3,148
Furniture and equipment	1,693	1,491	4,657	4,356
Office supplies and postage	432	516	1,327	1,487
Advertising and business development	584	628	1,821	2,123
Outside services	2,767	2,077	7,692	5,943
FDIC insurance assessment	226	217	657	636
Other noninterest expense	434	671	1,688	2,033
Noninterest expenses	15,955	14,821	46,891	44,433
Income before income taxes	12,640	12,274	38,736	34,355
Income taxes	2,590	3,722	7,765	10,472
Net income	$ 10,050	$ 8,552	$ 30,971	$ 23,883
Earnings per share:
Basic (in dollars per share)	$ 1.07	$ 0.92	$ 3.30	$ 2.56
Diluted (in dollars per share)	$ 1.07	$ 0.92	$ 3.30	$ 2.56
Trust fees
Noninterest income:
Fee income	$ 2,105	$ 1,980	$ 7,753	$ 5,883
Service charges and fees
Noninterest income:
Fee income	$ 2,839	$ 2,197	$ 7,475	$ 6,557

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 10,050	$ 8,552	$ 30,971	$ 23,883
Securities:
Net change in unrealized (loss) income on securities available for sale	(1,321)	(302)	(3,849)	2,797
Reclassification adjustment for net gains realized in net income	0	0	0	0
Income taxes	330	116	960	(1,070)
Other comprehensive (loss) income on securities available for sale	(991)	(186)	(2,889)	1,727
Derivatives used in cash flow hedging relationships:
Net change in unrealized income on derivatives	361	259	1,887	474
Income taxes	(90)	(99)	(470)	(181)
Other comprehensive income on cash flow hedges	271	160	1,417	293
Other comprehensive (loss) income, net of tax	(720)	(26)	(1,472)	2,020
Comprehensive income	$ 9,330	$ 8,526	$ 29,499	$ 25,903

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Unearned ESOP Shares [Member]	Treasury Stock [Member]	Maximum Cash Obligation Related To ESOP Shares [Member]
Beginning Balance at Dec. 31, 2016	$ 289,270	$ 44,606	$ 319,982	$ (3,359)		$ (31,178)	$ (40,781)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of 92,621 and 94,097 shares of common stock for 9 months ended September 30, 2017 and 2018, respectively	4,263	4,208				55
Issuance 4,483 and 6,149 shares of common stock under the employee stock purchase plan for 9 months ended September 30, 2017 and 2018, respectively	210	210
Unearned restricted stock compensation	277	277
Forfeiture of 2,934 and 2,996 shares of common stock for 9 months ended September 30, 2017 and 2018, respectively		(118)
Share-based compensation	11	11
Income tax benefit related to share-based compensation	0	0
Change related to ESOP shares	(1,690)						(1,690)
Net income	23,883		23,883
Cash dividends ($0.70 and $0.75 per share for 9 months ended September 30, 2017 and 2018, respectively)	(6,485)		(6,485)
Purchase of 40,265 and 97,081 shares of common stock for 9 months ended September 30, 2017 and 2018, respectively	(2,075)					(2,075)
Other comprehensive income (loss)	2,020			2,020
Ending Balance at Sep. 30, 2017	309,566	49,194	337,380	(1,339)	0	(33,198)	(42,471)
Beginning Balance at Dec. 31, 2017	311,716	48,930	341,558	(2,446)	0	(33,018)	(43,308)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of 92,621 and 94,097 shares of common stock for 9 months ended September 30, 2017 and 2018, respectively	5,100	2,748				2,352
Issuance 4,483 and 6,149 shares of common stock under the employee stock purchase plan for 9 months ended September 30, 2017 and 2018, respectively	313	313
Unearned restricted stock compensation	372	372
Forfeiture of 2,934 and 2,996 shares of common stock for 9 months ended September 30, 2017 and 2018, respectively	(140)	(140)
Change related to ESOP shares	(4,285)						(4,285)
Net income	30,971		30,971
Cash dividends ($0.70 and $0.75 per share for 9 months ended September 30, 2017 and 2018, respectively)	(7,002)		(7,002)
Reclassification of stranded tax effects due to the Tax Cuts and Jobs Act			526	(526)
Purchase of 40,265 and 97,081 shares of common stock for 9 months ended September 30, 2017 and 2018, respectively	(5,589)					(5,589)
Other comprehensive income (loss)	(1,472)			(1,472)
Ending Balance at Sep. 30, 2018	$ 329,984	$ 52,223	$ 366,053	$ (4,444)	$ 0	$ (36,255)	$ (47,593)

CONSOLIDATED STATEMENTS OF ST_2

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Statement of Stockholders' Equity [Abstract]
Issuance of common stock (in shares)	94,097	92,621
Issuance of common stock purchased under the employee stock purchase plan (in shares)	6,149	4,483
Forfeiture of common stock (in shares)	2,996	2,934
Cash dividends (in dollars per share)	$ 0.75	$ 0.70
Purchase of common stock (in shares)	97,081	40,265

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash Flows from Operating Activities
Net income	$ 30,971	$ 23,883
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Depreciation	2,463	2,270
Provision for loan losses	1,539	1,827
Share-based compensation	0	11
Forfeiture of common stock	(140)	(118)
Compensation expensed through issuance of common stock	387	208
Provision for deferred income taxes	(379)	(1,513)
Net loss (gain) on sale of other real estate owned and other repossessed assets	3	(89)
Increase in accrued interest receivable	(1,938)	(2,363)
Amortization of premium on investment securities, net	370	437
(Increase) decrease in other assets	(2,120)	1,049
(Decrease) increase in accrued interest payable and other liabilities	(1,358)	1,288
Loans originated for sale	(110,694)	(109,522)
Proceeds on sales of loans	113,680	113,730
Net gain on sales of loans	(1,227)	(1,119)
Net cash and cash equivalents provided by operating activities	31,557	29,979
Cash Flows from Investing Activities
Proceeds from maturities of investment securities available for sale	51,224	48,937
Purchases of investment securities available for sale	(59,757)	(37,735)
Loans made to customers, net of collections	(96,159)	(141,994)
Proceeds on sale of other real estate owned and other repossessed assets	59	364
Purchases of property and equipment	(2,088)	(2,210)
Income from tax credit real estate, net	912	547
Net cash and cash equivalents used in investing activities	(105,809)	(132,091)
Cash Flows from Financing Activities
Net increase in deposits	200,187	36,730
Net decrease in other borrowings	0	(19,728)
Net (decrease) increase in FHLB borrowings	(80,000)	88,000
Issuance of common stock, net of costs	4,713	3,817
Stock options exercised	0	238
Purchase of treasury stock	(5,589)	(2,075)
Proceeds from the issuance of common stock through the employee stock purchase plan	313	210
Dividends paid	(7,002)	(6,485)
Net cash and cash equivalents provided by financing activities	112,622	100,707
(Increase) decrease in cash and cash equivalents	38,370	(1,405)
Cash and cash equivalents:
Beginning of period	154,353	38,197
End of period	192,723	36,792
Cash payments for:
Interest paid to depositors	13,270	6,635
Interest paid on other obligations	5,182	6,087
Income taxes paid	7,188	10,530
Noncash activities:
Increase in maximum cash obligation related to ESOP shares	4,285	1,690
Transfers to other real estate owned	65	182
Sale and financing of other real estate owned	$ 0	$ 262

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation: The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial reporting and with instructions for Form 10-Q and Regulation S-X. These financial statements include all adjustments (consisting of normal recurring accruals) which in the opinion of management are considered necessary for the fair presentation of the financial position and results of operations for the periods shown. Certain prior year amounts have been reclassified to conform to the current year presentation. The Company considers that it operates as one business segment, a commercial bank. Operating results for the nine month period ended September 30, 2018 are not necessarily indicative of the results that may be expected for the fiscal year ending December 31, 2018 . For further information, refer to the consolidated financial statements and footnotes thereto included in the Form 10-K Annual Report of Hills Bancorporation and subsidiary (the “Company”) for the year ended December 31, 2017 filed with the Securities Exchange Commission on March 5, 2018 . The consolidated balance sheet as of December 31, 2017 , has been derived from the audited consolidated financial statements for that period. The Company evaluated subsequent events through the filing date of its quarterly report on Form 10-Q with the SEC. Revenue Recognition Accounting Standards Codification ("ASC") 606, Revenue from Contracts with Customers ("ASC 606"), establishes principles for reporting information about the nature, amount, timing and uncertainty of revenue and cash flows arising from the Company’s contracts to provide goods or services to customers. The core principle requires an entity to recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration that it expects to be entitled to receive in exchange for those goods or services recognized as performance obligations are satisfied. The majority of the Company’s revenue-generating transactions are not subject to ASC 606, including revenue generated from financial instruments, such as loans, letters of credit and investment securities as these activities are not subject to the requirements of ASC 606. Interest income on loans and investment securities is recognized on the accrual method in accordance with written contracts. Descriptions of the Company’s revenue-generating activities that are within the scope of ASC 606 are the following: Service charges and fees on deposit accounts represent general service fees for monthly account maintenance and activity- or transaction-based fees and consist of transaction-based revenue which includes interchange income, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when the Company’s performance obligation is completed which is generally monthly for account maintenance services or when a transaction has been completed (such as a wire transfer). Payment for such performance obligations are generally received at the time the performance obligations are satisfied. Trust income represents monthly fees due from wealth management customers as consideration for managing the customers' assets. Wealth management and trust services include custody of assets, investment management, fees for trust services and similar fiduciary activities. Revenue is recognized when our performance obligation is completed each month, which is generally the time that payment is received. Effect of New Financial Accounting Standards: In May 2014, The FASB and International Accounting Standards Board (IASB) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The core principle of ASU 2014-09 is that a company should recognize revenue to depict the transfer of promised good or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. ASU 2014-09 is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. The adoption of ASU 2014-09 by the Company did not have a material impact on the recognition of revenue though did require additional disclosures on our material noninterest income streams discussed in revenue recognition above. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities. ASU 2016-01 created Subtopic 321-10, Investments-Equity Securities which is applicable to all entities except those in industries that account for substantially all investments at fair value through earnings or the change in net assets. Under this new subtopic, equity securities are generally required to be measured at fair value with unrealized holding gains and losses reflected in net income. ASU 2016-01 is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. The Company adopted ASU 2016-01 for the period ending March 31, 2018. There was no material impact on the financial statements however it required a change in disclosure and related methodology located in Note 6 Fair Value Measurements. In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases . The ASU provides guidance requiring lessees to recognize right-of-use (ROU) assets and lease liabilities for all leases other than those that meet the definition of short-term leases. For short-term leases, lessees may elect an accounting policy by class of underlying asset under which these assets and liabilities are not recognized and lease payments are generally recognized over the lease term on a straight-line basis. Under this new ASU, lessees will recognize right-of use assets and lease liabilities for most leases currently accounted for as operating leases under generally accepted accounting principles. For public companies, ASU 2016-02 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company is in the process of analyzing a comprehensive list of lease agreements. We expect to adopt the new standard on January 1, 2019 and use the effective date as our date of initial application. Consequently, financial information will not be updated and the disclosures required under the new standard will not be provided for dates and periods before January 1, 2019. The new standard provides a number of optional practical expedients in transition. We expect to elect the 'package of practical expedients', which permits us not to reassess under the new standard our prior conclusions about lease identification, lease classification and initial direct costs. We do not expect to elect the use-of-hindsight or the practical expedient pertaining to land easements; the latter not being applicable to us. We expect that this standard will not have a material effect on our financial statements. While we continue to assess all of the effects of adoption, we currently believe the most significant effects relate to the recognition of new ROU assets and lease liabilities on our balance sheet for our equipment and real estate operating leases. We do not expect a significant change in our leasing activities between now and adoption. On adoption, we currently expect to recognize additional operating liabilities ranging from $3 million to $3.5 million , with corresponding ROU assets of the same amount based on the present value of the remaining minimum rental payments under current leasing standards for existing operating leases. In March 2016, the FASB issued ASU No. 2016-04, Liabilities - Extinguishments of Liabilities (Subtopic 405-20), Recognition of Breakage for Certain Prepaid Stored-Value Products . ASU 2016-04 applies to all entities that offer certain prepaid stored - value products. The ASU provides guidance for the derecognition of financial liabilities related to the issuance of these products and aligns the recognition of breakage to current authoritative guidance. For public companies, ASU 2016-04 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. The Company adopted ASU 2016-04 for the period ending March 31, 2018. There was no material impact on the financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments (CECL). The ASU changes the way entities recognize impairment of financial assets by requiring immediate recognition of estimated credit losses expected to occur over the remaining life of many financial assets. Under the CECL model, we will be required to present certain financial assets carried at amortized cost, such as loans held for investment and held-to-maturity debt securities, at the net amount expected to be collected. The measurement of expected credit losses is to be based on information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. This measurement will take place at the time the financial asset is first added to the balance sheet and periodically thereafter. This differs significantly from the "incurred loss" model required under current GAAP, which delays recognition until it is probable a loss has been incurred. Accordingly, we expect that the adoption of the CECL model will materially affect how we determine our allowance for loan losses and could require us to significantly increase our allowance. For public companies, ASU 2016-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, early adoption is permitted for the fiscal year beginning after December 15, 2018. The Company has implemented a software solution to assist in the analysis of historical loan data to determine the CECL model that will be implemented and is in the process of validating the historical loan data in the software solution. The Company anticipates running parallel calculations of the "incurred loss" and CECL models for the quarter ending March 31, 2019. We expect to recognize a one-time cumulative-effect adjustment to our allowance for loan losses as of the beginning of the first reporting period in which the new standard is adopted. The amount of the one-time cumulative-effect adjustment has not yet been determined. In January 2017, the FASB issued ASU No. 2017-03, Accounting Changes and Error Corrections (Topic 250) and Investments - Equity Method and Joint Ventures (Topic 323), Amendments to SEC Paragraphs Pursuant to Staff Announcements at the September 22, 2016 and November 17, 2016 EITF Meetings. This ASU adds an SEC paragraph and amends other Topics pursuant to an SEC staff Announcement made at the September 22, 2016 Emerging Issues Task Force (EITF) meeting. The SEC paragraph applies to ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606); ASU No. 2016-02, Leases (Topic 842); and ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU provides that a company should evaluate ASUs that have not yet been adopted to determine the appropriate financial statement disclosures about the potential material effects of those ASUs on the financial statements when adopted. If the company does not know or cannot reasonably estimate the impact that adoption of the ASUs referenced in this announcement is expected to have on the financial statements, then in addition to making a statement to that effect, the company should consider additional qualitative financial statement disclosures to assist the reader in assessing the significance of the impact that the standard will have on the financial statements of the company when adopted. Additional qualitative disclosures should include a description of the effect of the accounting policies that the company expects to apply and a comparison to the company's current accounting policies. Also, the company should describe the status of its process to implement the new standards and the significant implementation matters yet to be addressed. In January 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 250), Simplifying the Test for Goodwill Impairment. The ASU simplifies the goodwill impairment test by requiring a company to perform its annual or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized when the carrying amount exceeds fair value. For public companies, ASU 2017-04 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The adoption of ASU No. 2017-04 by the Company is not expected to have a material impact. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities. This ASU requires companies to change the recognition and presentation of the effects of hedge accounting by eliminating the requirement to separately measure and report hedge ineffectiveness and requiring companies to present all of the elements of hedge accounting that affect earnings in the same income statement line as the hedged item. Furthermore, the standard eases the requirements for effectiveness testing, hedge documentation and applying the critical terms match method and introduces new alternatives that will permit companies to reduce the risk of material error corrections if they misapply the shortcut method. For public companies, ASU 2017-12 is effective for fiscal years, and interim periods within those fiscal years beginning after December 15, 2018. The adoption of ASU 2017-12 by the Company is not expected to have a material impact. In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220), Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. This ASU allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. ASU 2018-02 is effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The Company adopted ASU 2018-02 for the period ending March 31, 2018 and elected the specific identification method accounting policy. There was a $0.53 million reclassification recorded in stockholders' equity. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting . The amendments in this ASU expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-07 is effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. The adoption of ASU 2018-07 by the Company is not expected to have a material impact. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement . The amendments in this ASU modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement, including removal of the requirement to disclose the valuation processes for Level 3 fair value measurements and the additional requirement to disclose the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. ASU 2018-13 is effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted upon issuance of this ASU. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this ASU and delay adoption of the additional disclosures until their effective date. The adoption of ASU 2018-13 by the Company is not expected to have a material impact. In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40), Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangements That Is a Service Contract. The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 is effective for public business entities for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption of the amendments in this ASU is permitted, including adoption in any interim period, for all entities. The amendments in this ASU should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company is in the process of evaluating the impact of this ASU on the financial statements.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per share is computed using the weighted average number of actual common shares outstanding during the period. Diluted earnings per share reflects the potential dilution that would occur from the exercise of common stock options outstanding. ESOP shares are considered outstanding for this calculation unless unearned. The computation of basic and diluted earnings per share for the periods presented is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Common shares outstanding at the beginning of the period 9,373,666 9,329,514 9,335,154 9,264,227 Weighted average number of net shares (redeemed) issued (22,223 ) (4,596 ) 40,123 64,144 Weighted average shares outstanding (basic) 9,351,443 9,324,918 9,375,277 9,328,371 Weighted average of potential dilutive shares attributable to stock options granted, computed under the treasury stock method 4,245 3,559 4,067 4,874 Weighted average number of shares (diluted) 9,355,688 9,328,477 9,379,344 9,333,245 Net income (In thousands) $ 10,050 $ 8,552 $ 30,971 $ 23,883 Earnings per share: Basic $ 1.07 $ 0.92 $ 3.30 $ 2.56 Diluted $ 1.07 $ 0.92 $ 3.30 $ 2.56

Other Comprehensive Income (Los

Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss) The following table summarizes the balances of each component of accumulated other comprehensive income (AOCI), included in stockholders’ equity, at September 30, 2018 and December 31, 2017 : September 30, December 31, 2017 (amounts in thousands) Net unrealized loss on available-for-sale securities $ (4,990 ) $ (1,141 ) Net unrealized loss on derivatives used for cash flow hedges (932 ) (2,819 ) Tax effect $ 1,478 $ 1,514 Net-of-tax amount $ (4,444 ) $ (2,446 )

Securities

Securities	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Securities	Securities The carrying values of investment securities at September 30, 2018 and December 31, 2017 are summarized in the following table (dollars in thousands): September 30, 2018 December 31, 2017 Amount Percent Amount Percent Securities available for sale U.S. Treasury $ 82,353 28.18 % $ 54,318 19.05 % Other securities (FHLB, FHLMC and FNMA) 34,733 11.88 43,959 15.42 State and political subdivisions 175,216 59.94 186,878 65.53 Total securities available for sale $ 292,302 100.00 % $ 285,155 100.00 % Investment securities have been classified in the consolidated balance sheets according to management’s intent. Available-for-sale securities consist of debt securities not classified as trading or held to maturity. Available-for-sale securities are stated at fair value, and unrealized holding gains and losses, net of the related deferred tax effect, are reported as a separate component of stockholders' equity. There were no trading or held to maturity securities as of September 30, 2018 or December 31, 2017 . The carrying amount of available-for-sale securities and their approximate fair values were as follows as of September 30, 2018 and December 31, 2017 (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value September 30, 2018: U.S. Treasury $ 83,949 $ — $ (1,596 ) $ 82,353 Other securities (FHLB, FHLMC and FNMA) 35,398 1 (666 ) 34,733 State and political subdivisions 177,945 129 (2,858 ) 175,216 Total $ 297,292 $ 130 $ (5,120 ) $ 292,302 December 31, 2017: U.S. Treasury $ 54,696 $ — $ (378 ) $ 54,318 Other securities (FHLB, FHLMC and FNMA) 44,470 1 (512 ) 43,959 State and political subdivisions 187,130 722 (974 ) 186,878 Total $ 286,296 $ 723 $ (1,864 ) $ 285,155 The amortized cost and estimated fair value of available-for-sale securities classified according to their contractual maturities at September 30, 2018 , were as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 41,457 $ 41,340 Due after one year through five years 180,463 177,642 Due after five years through ten years 74,811 72,759 Due over ten years 561 561 Total $ 297,292 $ 292,302 As of September 30, 2018 investment securities with a carrying value of $12.19 million were pledged to collateralize repurchase agreements, derivative financial instruments, and other borrowings. The following table shows the fair value, gross unrealized losses and the percentage of fair value represented by gross unrealized losses of applicable investment securities owned by the Company, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at September 30, 2018 and December 31, 2017 (in thousands): Less than 12 months 12 months or more Total September 30, 2018 # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % U.S. Treasury 24 $ 58,023 $ (987 ) 1.70 % 10 $ 24,330 $ (609 ) 2.50 % 34 $ 82,353 $ (1,596 ) 1.94 % Other securities (FHLB, FHLMC and FNMA) 1 2,494 (9 ) 0.36 13 32,239 (657 ) 2.04 14 34,733 (666 ) 1.92 State and political subdivisions 377 94,638 (1,490 ) 1.57 142 33,670 (1,368 ) 4.06 519 128,308 (2,858 ) 2.23 Total temporarily impaired securities 402 $ 155,155 $ (2,486 ) 1.60 % 165 $ 90,239 $ (2,634 ) 2.92 % 567 $ 245,394 $ (5,120 ) 2.09 % Less than 12 months 12 months or more Total December 31, 2017 # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % U.S. Treasury 22 $ 54,318 $ (378 ) 0.70 % — $ — $ — — % 22 $ 54,318 $ (378 ) 0.70 % Other securities (FHLB, FHLMC and FNMA) 9 21,411 (83 ) 0.39 9 22,547 (429 ) 1.90 18 43,958 (512 ) 1.16 State and political subdivisions 241 58,803 (573 ) 0.97 65 14,944 (401 ) 2.68 306 73,747 (974 ) 1.32 Total temporarily impaired securities 272 $ 134,532 $ (1,034 ) 0.77 % 74 $ 37,491 $ (830 ) 2.21 % 346 $ 172,023 $ (1,864 ) 1.08 % The Company considered the following information in reaching the conclusion that the impairments disclosed in the table above are temporary and not other-than-temporary impairments. None of the unrealized losses in the above table was due to the deterioration in the credit quality of any of the issues that might result in the non-collection of contractual principal and interest. The unrealized losses are due to changes in interest rates. The Company has not recognized any unrealized loss in income because management does not have the intent to sell the securities included in the previous table. Management has concluded that it is more likely than not that the Company will not be required to sell these securities prior to recovery of the amortized cost basis.

Loans

Loans	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Loans	Loans Classes of loans are as follows: September 30, December 31, (Amounts In Thousands) Agricultural $ 79,155 $ 88,580 Commercial and financial 214,681 218,632 Real estate: Construction, 1 to 4 family residential 65,932 69,738 Construction, land development and commercial 106,012 109,595 Mortgage, farmland 230,032 215,286 Mortgage, 1 to 4 family first liens 899,937 831,591 Mortgage, 1 to 4 family junior liens 149,312 144,200 Mortgage, multi-family 347,660 336,810 Mortgage, commercial 381,966 361,196 Loans to individuals 27,946 26,417 Obligations of state and political subdivisions 53,149 57,626 $ 2,555,782 $ 2,459,671 Net unamortized fees and costs 948 894 $ 2,556,730 $ 2,460,565 Less allowance for loan losses 31,010 29,400 $ 2,525,720 $ 2,431,165 Changes in the allowance for loan losses, the allowance for loan losses applicable to impaired loans and the related loan balance of impaired loans for the three and nine months ended September 30, 2018 were as follows: Three Months Ended September 30, 2018 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,071 $ 5,040 $ 3,054 $ 3,475 $ 8,902 $ 5,697 $ 1,271 $ 29,510 Charge-offs (68 ) (241 ) — — (280 ) (107 ) (197 ) (893 ) Recoveries 74 415 2 10 187 80 32 800 Provision (47 ) (133 ) (188 ) 50 1,756 193 (38 ) 1,593 Ending balance $ 2,030 $ 5,081 $ 2,868 $ 3,535 $ 10,565 $ 5,863 $ 1,068 $ 31,010 Nine Months Ended September 30, 2018 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,294 $ 4,837 $ 2,989 $ 3,669 $ 8,668 $ 5,700 $ 1,243 $ 29,400 Charge-offs (72 ) (447 ) — — (607 ) (161 ) (420 ) (1,707 ) Recoveries 102 856 147 29 433 97 114 1,778 Provision (294 ) (165 ) (268 ) (163 ) 2,071 227 131 1,539 Ending balance $ 2,030 $ 5,081 $ 2,868 $ 3,535 $ 10,565 $ 5,863 $ 1,068 $ 31,010 Ending balance, individually evaluated for impairment $ 118 $ 1,165 $ 3 $ — $ 91 $ 40 $ 48 $ 1,465 Ending balance, collectively evaluated for impairment $ 1,912 $ 3,916 $ 2,865 $ 3,535 $ 10,474 $ 5,823 $ 1,020 $ 29,545 Loans: Ending balance $ 79,155 $ 214,681 $ 171,944 $ 230,032 $ 1,049,249 $ 729,626 $ 81,095 $ 2,555,782 Ending balance, individually evaluated for impairment $ 2,342 $ 3,288 $ 927 $ 3,729 $ 6,728 $ 8,217 $ 48 $ 25,279 Ending balance, collectively evaluated for impairment $ 76,813 $ 211,393 $ 171,017 $ 226,303 $ 1,042,521 $ 721,409 $ 81,047 $ 2,530,503 Changes in the allowance for loan losses for the three and nine months ended September 30, 2017 were as follows: Three Months Ended September 30, 2017 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,341 $ 4,586 $ 3,165 $ 4,009 $ 8,340 $ 5,414 $ 1,095 $ 28,950 Charge-offs (27 ) (21 ) — (3 ) (55 ) (86 ) (113 ) (305 ) Recoveries 56 219 33 — 203 7 57 575 Provision 92 (43 ) (182 ) 2 98 107 56 130 Ending balance $ 2,462 $ 4,741 $ 3,016 $ 4,008 $ 8,586 $ 5,442 $ 1,095 $ 29,350 Nine Months Ended September 30, 2017 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,947 $ 4,531 $ 2,890 $ 3,417 $ 7,677 $ 4,045 $ 1,023 $ 26,530 Charge-offs (66 ) (478 ) (114 ) (3 ) (263 ) (130 ) (410 ) (1,464 ) Recoveries 123 882 443 — 570 236 203 2,457 Provision (542 ) (194 ) (203 ) 594 602 1,291 279 1,827 Ending balance $ 2,462 $ 4,741 $ 3,016 $ 4,008 $ 8,586 $ 5,442 $ 1,095 $ 29,350 Ending balance, individually evaluated for impairment $ 653 $ 913 $ 46 $ 784 $ 110 $ 409 $ 85 $ 3,000 Ending balance, collectively evaluated for impairment $ 1,809 $ 3,828 $ 2,970 $ 3,224 $ 8,476 $ 5,033 $ 1,010 $ 26,350 Loans: Ending balance $ 76,484 $ 214,199 $ 180,574 $ 208,982 $ 960,800 $ 694,771 $ 84,084 $ 2,419,894 Ending balance, individually evaluated for impairment $ 6,181 $ 2,985 $ 1,161 $ 8,179 $ 7,097 $ 8,097 $ 85 $ 33,785 Ending balance, collectively evaluated for impairment $ 70,303 $ 211,214 $ 179,413 $ 200,803 $ 953,703 $ 686,674 $ 83,999 $ 2,386,109 The following table presents the credit quality indicators by type of loans in each category as of September 30, 2018 and December 31, 2017 , respectively (amounts in thousands): Agricultural Commercial and Financial Real Estate: Construction, 1 to 4 family residential Real Estate: Construction, land development and commercial September 30, 2018 Grade: Excellent $ 2,466 $ 2,858 $ — $ 393 Good 13,521 46,227 11,782 22,648 Satisfactory 37,824 118,659 39,457 57,043 Monitor 19,630 33,612 13,516 24,687 Special Mention 901 7,095 782 178 Substandard 4,813 6,230 395 1,063 Total $ 79,155 $ 214,681 $ 65,932 $ 106,012 Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family first liens Real Estate: Mortgage, 1 to 4 family junior liens Real Estate: Mortgage, multi- family September 30, 2018 Grade: Excellent $ 3,700 $ 2,360 $ 524 $ 22,139 Good 52,301 33,045 3,931 70,444 Satisfactory 123,898 741,877 136,420 176,519 Monitor 36,890 91,612 4,930 59,380 Special Mention 3,983 11,031 1,549 12,910 Substandard 9,260 20,012 1,958 6,268 Total $ 230,032 $ 899,937 $ 149,312 $ 347,660 Real Estate: Mortgage, commercial Loans to individuals Obligations of state and political subdivisions Total September 30, 2018 Grade: Excellent $ 34,798 $ — $ 8,329 $ 77,567 Good 92,947 119 15,623 362,588 Satisfactory 181,337 26,800 18,522 1,658,356 Monitor 58,165 705 10,675 353,802 Special Mention 10,842 206 — 49,477 Substandard 3,877 116 — 53,992 Total $ 381,966 $ 27,946 $ 53,149 $ 2,555,782 Agricultural Commercial and Financial Real Estate: Construction, 1 to 4 family residential Real Estate: Construction, land development and commercial December 31, 2017 Grade: Excellent $ 2,585 $ 10,264 $ — $ 2,548 Good 15,755 51,620 4,710 27,296 Satisfactory 40,886 116,375 47,995 35,749 Monitor 17,009 29,392 15,188 39,760 Special Mention 6,898 5,576 1,845 3,358 Substandard 5,447 5,405 — 884 Total $ 88,580 $ 218,632 $ 69,738 $ 109,595 Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family first liens Real Estate: Mortgage, 1 to 4 family junior liens Real Estate: Mortgage, multi- family December 31, 2017 Grade: Excellent $ 4,751 $ 2,392 $ 489 $ 16,564 Good 54,409 30,094 4,527 75,768 Satisfactory 109,724 689,645 130,451 195,652 Monitor 32,655 76,766 4,881 42,373 Special Mention 5,306 12,072 1,834 — Substandard 8,441 20,622 2,018 6,453 Total $ 215,286 $ 831,591 $ 144,200 $ 336,810 Real Estate: Mortgage, commercial Loans to individuals Obligations of state and political subdivisions Total December 31, 2017 Grade: Excellent $ 30,355 $ 1 $ 8,794 $ 78,743 Good 98,434 118 30,607 393,338 Satisfactory 179,417 25,445 14,693 1,586,032 Monitor 43,786 500 3,532 305,842 Special Mention 6,303 182 — 43,374 Substandard 2,901 171 — 52,342 Total $ 361,196 $ 26,417 $ 57,626 $ 2,459,671 The below are descriptions of the credit quality indicators: Excellent – Excellent rated loans are prime quality loans covered by highly liquid collateral with generous margins or supported by superior current financial conditions reflecting substantial net worth, relative to total credit extended, and based on assets of a stable and non-speculative nature whose values can be readily verified. Identified repayment source or cash flow is abundant and assured. Good – Good rated loans are adequately secured by readily marketable collateral or good financial condition characterized by liquidity, flexibility and sound net worth. Loans are supported by sound primary and secondary payment sources and timely and accurate financial information. Satisfactory – Satisfactory rated loans are loans to borrowers of average financial means not especially vulnerable to changes in economic or other circumstances, where the major support for the extension is sufficient collateral of a marketable nature, and the primary source of repayment is seen to be clear and adequate. Monitor – Monitor rated loans are identified by management as warranting special attention for a variety of reasons that may bear on ultimate collectability. This may be due to adverse trends, a particular industry, loan structure, or repayment that is dependent on projections, or a one-time occurrence. Special Mention – Special mention rated loans are supported by a marginal payment capacity and are marginally protected by collateral. There are identified weaknesses that if not monitored and corrected may adversely affect the Company’s credit position. A special mention credit would typically have a weakness in one of the general categories (cash flow, collateral position or payment history) but not in all categories. Substandard – Substandard loans are not adequately supported by the paying capacity of the borrower and may be inadequately collateralized. These loans have a well-defined weakness or weaknesses. For these loans, it is more probable than not that the Company could sustain some loss if the deficiency(ies) is not corrected. Past due loans as of September 30, 2018 and December 31, 2017 were as follows: 30 - 59 Days Past Due 60 - 89 Days Past Due 90 Days or More Past Due Total Past Due Current Total Loans Receivable Accruing Loans Past Due 90 Days or More (Amounts In Thousands) September 30, 2018 Agricultural $ 474 $ 84 $ 158 $ 716 $ 78,439 $ 79,155 $ — Commercial and financial 991 545 — 1,536 213,145 214,681 — Real estate: Construction, 1 to 4 family residential 566 437 — 1,003 64,929 65,932 — Construction, land development and commercial 458 — — 458 105,554 106,012 — Mortgage, farmland 240 751 — 991 229,041 230,032 — Mortgage, 1 to 4 family first liens 780 2,225 2,604 5,609 894,328 899,937 338 Mortgage, 1 to 4 family junior liens 59 88 — 147 149,165 149,312 — Mortgage, multi-family — 152 — 152 347,508 347,660 — Mortgage, commercial 135 349 — 484 381,482 381,966 — Loans to individuals 149 53 1 203 27,743 27,946 — Obligations of state and political subdivisions — — — — 53,149 53,149 — $ 3,852 $ 4,684 $ 2,763 $ 11,299 $ 2,544,483 $ 2,555,782 $ 338 December 31, 2017 Agricultural $ 324 $ — $ 269 $ 593 $ 87,987 $ 88,580 $ — Commercial and financial 447 20 93 560 218,072 218,632 — Real estate: Construction, 1 to 4 family residential — — — — 69,738 69,738 — Construction, land development and commercial 246 — — 246 $ 109,349 109,595 — Mortgage, farmland 269 — — 269 215,017 215,286 — Mortgage, 1 to 4 family first liens 5,143 1,750 2,939 9,832 $ 821,759 831,591 971 Mortgage, 1 to 4 family junior liens 579 116 — 695 143,505 144,200 — Mortgage, multi-family — — — — $ 336,810 336,810 — Mortgage, commercial 307 178 16 501 360,695 361,196 — Loans to individuals 206 55 6 267 $ 26,150 26,417 — Obligations of state and political subdivisions — — — — 57,626 57,626 — $ 7,521 $ 2,119 $ 3,323 $ 12,963 $ 2,446,708 $ 2,459,671 $ 971 The Company does not have a material amount of loans that are past due less than 90 days where there are serious doubts as to the ability of the borrowers to comply with the loan repayment terms. Certain impaired loan information by loan type at September 30, 2018 and December 31, 2017 , was as follows: September 30, 2018 December 31, 2017 Non-accrual loans (1) Accruing loans past due 90 days or more TDR loans Non- accrual loans (1) Accruing loans past due 90 days or more TDR loans (Amounts In Thousands) (Amounts In Thousands) Agricultural $ 1,401 $ — $ 72 $ 1,651 $ — $ 2,309 Commercial and financial 489 — 1,845 825 — 1,943 Real estate: Construction, 1 to 4 family residential — — — — — — Construction, land development and commercial — — 330 — — 339 Mortgage, farmland 1,167 — 3,313 1,391 — 1,451 Mortgage, 1 to 4 family first liens 5,064 338 1,302 4,407 971 1,357 Mortgage, 1 to 4 family junior liens — — 25 7 — 25 Mortgage, multi-family 152 — — 218 — — Mortgage, commercial 1,049 — 948 597 — 1,046 $ 9,322 $ 338 $ 7,835 $ 9,096 $ 971 $ 8,470 (1) There were $4.15 million and $3.62 million of TDR loans included within nonaccrual loans as of September 30, 2018 and December 31, 2017 , respectively. Loans 90 days or more past due that are still accruing interest decreased $0.63 million from December 31, 2017 to September 30, 2018 due to a decrease in the number of accruing loans past due 90 days or more and a decrease in the average accruing balance of loans past due greater than 90 days. As of September 30, 2018 there were 3 accruing loans past due 90 days or more. The average accruing loans past due as of September 30, 2018 are $0.11 million . There were 8 accruing loans past due 90 days or more as of December 31, 2017 and the average loan balance was $0.12 million . The accruing loans past due 90 days or more balances are believed to be adequately collateralized and the Company expects to collect all principal and interest as contractually due under these loans. The Company may modify the terms of a loan to maximize the collection of amounts due. Such a modification is considered a troubled debt restructuring (“TDR”). In most cases, the modification is either a reduction in interest rate, conversion to interest only payments or an extension of the maturity date. The borrower is experiencing financial difficulties or is expected to experience difficulties in the near-term, so a concessionary modification is granted to the borrower that would otherwise not be considered. TDR loans accrue interest as long as the borrower complies with the revised terms and conditions and has demonstrated repayment performance at a level commensurate with the modified terms over several payment cycles. Below is a summary of information for TDR loans as of September 30, 2018 and December 31, 2017 : September 30, 2018 December 31, 2017 Number of contracts Recorded investment Commitments outstanding Number of contracts Recorded investment Commitments outstanding (Amounts In Thousands) (Amounts In Thousands) Agricultural 4 $ 1,306 $ 582 9 $ 3,628 $ 321 Commercial and financial 13 2,269 85 14 2,575 169 Real estate: Construction, 1 to 4 family residential — — — — — 16 Construction, land development and commercial 2 330 — 2 339 — Mortgage, farmland 8 4,407 — 7 2,761 — Mortgage, 1 to 4 family first liens 17 1,760 — 13 1,442 — Mortgage, 1 to 4 family junior liens 1 25 — 1 25 24 Mortgage, multi-family — — — — — — Mortgage, commercial 9 1,885 — 8 1,324 — Loans to individuals — — — — — — 54 $ 11,982 $ 667 54 $ 12,094 $ 530 The following is a summary of TDR loans that were modified during the three and nine months ended September 30, 2018 : Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Number of contracts Pre-modification recorded investment Post-modification recorded investment Number of contracts Pre-modification recorded investment Post-modification recorded investment (Amounts In Thousands) (Amounts In Thousands) Agricultural — $ — $ — — $ — $ — Commercial and financial 2 80 80 4 541 541 Real estate: Construction, 1 to 4 family residential — — — — — — Construction, land development and commercial — — — — — — Mortgage, farmland — — — 2 4,944 4,944 Mortgage, 1 to 4 family first lien — — — 6 627 627 Mortgage, 1 to 4 family junior liens — — — — — — Mortgage, multi-family — — — — — — Mortgage, commercial 1 578 578 2 852 852 3 $ 658 $ 658 14 $ 6,964 $ 6,964 The Company had commitments to lend $0.67 million in additional borrowings to restructured loan customers as of September 30, 2018 . The Company had commitments to lend $0.53 million in additional borrowings to restructured loan customers as of December 31, 2017 . These commitments were in the normal course of business. The additional borrowings were not used to facilitate payments on these loans. There were no TDR loans that were in payment default (defined as past due 90 days or more) during the period ended September 30, 2018 and none for the year ended December 31, 2017 . Information regarding impaired loans as of and for the three and nine months ended September 30, 2018 is as follows: September 30, 2018 Three Months Ended Nine Months Ended September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized With no related allowance recorded: (Amounts In Thousands) Agricultural $ 2,224 $ 2,525 $ — $ 2,850 $ 15 $ 1,905 $ 14 Commercial and financial 1,515 2,208 — 1,633 14 1,781 44 Real estate: Construction, 1 to 4 family residential 111 148 — 111 1 113 4 Construction, land development and commercial 330 347 — 331 3 334 10 Mortgage, farmland 3,729 4,147 — 3,744 32 3,126 67 Mortgage, 1 to 4 family first liens 5,562 7,162 — 5,708 10 5,827 29 Mortgage, 1 to 4 family junior liens — 256 — — — — — Mortgage, multi-family 152 218 — 153 — 156 — Mortgage, commercial 1,922 2,510 — 2,041 10 1,965 32 Loans to individuals — 14 — — — — — $ 15,545 $ 19,535 $ — $ 16,571 $ 85 $ 15,207 $ 200 With an allowance recorded: Agricultural $ 118 $ 118 $ 118 $ 118 $ 2 $ 184 $ 8 Commercial and financial 1,773 1,873 1,165 1,821 22 2,028 74 Real estate: Construction, 1 to 4 family residential — — — — — — — Construction, land development and commercial 486 486 3 492 6 495 17 Mortgage, farmland — — — — — — — Mortgage, 1 to 4 family first liens 1,142 1,198 88 1,147 10 1,169 30 Mortgage, 1 to 4 family junior liens 24 24 3 25 — 25 1 Mortgage, multi-family 6,067 6,067 39 6,083 69 6,123 207 Mortgage, commercial 76 76 1 76 1 77 3 Loans to individuals 48 48 48 54 2 66 6 $ 9,734 $ 9,890 $ 1,465 $ 9,816 $ 112 $ 10,167 $ 346 Total: Agricultural $ 2,342 $ 2,643 $ 118 $ 2,968 $ 17 $ 2,089 $ 22 Commercial and financial 3,288 4,081 1,165 3,454 36 3,809 118 Real estate: Construction, 1 to 4 family residential 111 148 — 111 1 113 4 Construction, land development and commercial 816 833 3 823 9 829 27 Mortgage, farmland 3,729 4,147 — 3,744 32 3,126 67 Mortgage, 1 to 4 family first liens 6,704 8,360 88 6,855 20 6,996 59 Mortgage, 1 to 4 family junior liens 24 280 3 25 — 25 1 Mortgage, multi-family 6,219 6,285 39 6,236 69 6,279 207 Mortgage, commercial 1,998 2,586 1 2,117 11 2,042 35 Loans to individuals 48 62 48 54 2 66 6 $ 25,279 $ 29,425 $ 1,465 $ 26,387 $ 197 $ 25,374 $ 546 Information regarding impaired loans as of December 31, 2017 is as follows: Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded: (Amounts In Thousands) Agricultural $ 1,822 $ 2,193 $ — Commercial and financial 1,725 2,487 — Real estate: Construction, 1 to 4 family residential 114 150 — Construction, land development and commercial 338 371 — Mortgage, farmland 2,523 2,902 — Mortgage, 1 to 4 family first liens 6,045 7,507 — Mortgage, 1 to 4 family junior liens 7 482 — Mortgage, multi-family 218 355 — Mortgage, commercial 1,564 2,274 — Loans to individuals — 14 — $ 14,356 $ 18,735 $ — With an allowance recorded: Agricultural $ 3,094 $ 3,149 $ 133 Commercial and financial 1,043 1,043 1,018 Real estate: Construction, 1 to 4 family residential — — — Construction, land development and commercial 505 505 39 Mortgage, farmland 5,439 5,439 238 Mortgage, 1 to 4 family first liens 577 593 63 Mortgage, 1 to 4 family junior liens 25 25 3 Mortgage, multi-family 6,179 6,179 480 Mortgage, commercial 79 79 2 Loans to individuals 190 190 190 $ 17,131 $ 17,202 $ 2,166 Total: Agricultural $ 4,916 $ 5,342 $ 133 Commercial and financial 2,768 3,530 1,018 Real estate: Construction, 1 to 4 family residential 114 150 — Construction, land development and commercial 843 876 39 Mortgage, farmland 7,962 8,341 238 Mortgage, 1 to 4 family first liens 6,622 8,100 63 Mortgage, 1 to 4 family junior liens 32 507 3 Mortgage, multi-family 6,397 6,534 480 Mortgage, commercial 1,643 2,353 2 Loans to individuals 190 204 190 $ 31,487 $ 35,937 $ 2,166 Impaired loans decreased $6.21 million from December 31, 2017 to September 30, 2018 . Impaired loans include any loan that has been placed on nonaccrual status, accruing loans past due 90 days or more and TDR loans. Impaired loans also include loans that, based on management’s evaluation of current information and events, the Company expects to be unable to collect in full according to the contractual terms of the original loan agreement. Impaired loans were 0.99% of loans held for investment as of September 30, 2018 and 1.28% as of December 31, 2017 . The decrease in impaired loans is due mainly to a decrease of $7.40 million in relationships with a specific allowance for losses, a $0.63 million decrease in 90 days or more accruing loans and a decrease in TDR loans of $0.11 million , and is offset by an increase in impaired loans without a specific allowance for losses of $1.19 million and an increase in nonaccrual loans of $0.23 million from December 31, 2017 to September 30, 2018 . The Company regularly reviews a substantial portion of the loans in the portfolio and assesses whether the loans are impaired in accordance with ASC 310. If the loans are impaired, the Company determines if a specific allowance is appropriate. In addition, the Company's management also reviews and, where determined necessary, provides allowances for particular loans based upon (1) reviews of specific borrowers and (2) management’s assessment of areas that management considers are of higher credit risk, including loans that have been restructured. Loans that are determined not to be impaired and for which there are no specific allowances are classified into one or more risk categories. Based upon the risk category assigned, the Company allocates a percentage, as determined by management, for a required allowance needed. The determination of the appropriate percentage begins with historical loss experience factors, which are then adjusted for levels and trends in past due loans, levels and trends in charged-off and recovered loans, trends in volume growth, trends in problem and watch loans, trends in restructured loans, local economic trends and conditions, industry and other conditions, and effects of changing interest rates. Specific allowances for losses on impaired loans are established if the loan balances exceed the net present value of the relevant future cash flows or the fair value of the relevant collateral based on updated appraisals and/or updated collateral analysis for the properties if the loan is collateral dependent. The Company may recognize a charge off or record a specific allowance related to an impaired loan if there is a collateral shortfall or it is unlikely the borrower can make all principal and interest payments as contractually due. For loans that are collateral dependent, losses are evaluated based on the portion of a loan that exceeds the fair market value of the collateral. In general, this is the amount that the carrying value of the loan exceeds the related appraised value less estimated costs to sell the collateral. Generally, it is the Company’s policy not to rely on appraisals that are older than one year prior to the date the impairment is being measured. The most recent appraisal values may be adjusted if, in the Company’s judgment, experience and other market data indicate that the property’s value, use, condition, exit market or other variable affecting its value may have changed since the appraisal was performed, consistent with the December 2006 joint interagency guidance on the allowance for loan losses. The charge off or loss adjustment supported by an appraisal is considered the minimum charge off. Any adjustments made to the appraised value are to provide an additional charge off or specific reserve based on the applicable facts and circumstances. In instances where there is an estimated decline in value, a specific reserve may be provided or a charge off taken pending confirmation of the amount of the loss from an updated appraisal. Upon receipt of the new appraisals, an additional specific reserve may be provided or charge off taken based on the appraised value of the collateral. On average, appraisals are obtained within one month of order.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The carrying value and estimated fair values of the Company's financial instruments as of September 30, 2018 are as follows: September 30, 2018 Carrying Amount Estimated Fair Value Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) (Amounts In Thousands) Financial instrument assets: Cash and cash equivalents $ 192,723 $ 192,723 $ 192,723 $ — $ — Investment securities 304,474 304,474 — 304,474 — Loans held for sale 3,403 3,403 — — 3,403 Loans Agricultural 77,125 79,007 — — 79,007 Commercial and financial 209,600 210,339 — — 210,339 Real estate: Construction, 1 to 4 family residential 64,755 65,949 — — 65,949 Construction, land development and commercial 104,321 102,867 — — 102,867 Mortgage, farmland 226,497 227,368 — — 227,368 Mortgage, 1 to 4 family first liens 891,649 867,383 — — 867,383 Mortgage, 1 to 4 family junior liens 147,983 143,265 — — 143,265 Mortgage, multi-family 344,900 336,147 — — 336,147 Mortgage, commercial 378,863 369,365 — — 369,365 Loans to individuals 27,303 27,765 — — 27,765 Obligations of state and political subdivisions 52,724 51,762 — — 51,762 Accrued interest receivable 12,710 12,710 — 12,710 — Total financial instrument assets $ 3,039,030 $ 2,994,527 $ 192,723 $ 317,184 $ 2,484,620 Financial instrument liabilities Deposits Noninterest-bearing deposits $ 374,927 $ 374,927 $ — $ 374,927 $ — Interest-bearing deposits 2,113,825 2,122,255 — 2,122,255 — Other borrowings — — — — — Federal Home Loan Bank borrowings 215,000 207,705 — 207,705 — Interest rate swaps 932 932 — 932 — Accrued interest payable 1,708 1,708 — 1,708 — Total financial instrument liabilities $ 2,706,392 $ 2,707,527 $ — $ 2,707,527 $ — Face Amount Financial instrument with off-balance sheet risk: Loan commitments $ 407,101 $ — $ — $ — $ — Letters of credit 7,841 — — — — Total financial instrument liabilities with off-balance-sheet risk $ 414,942 $ — $ — $ — $ — (1) Considered Level 1 under Accounting Standards Codification (“ASC”) Topic 820, Fair Value Measurements and Disclosures (“ASC 820”). (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. The carrying value and estimated fair values of the Company's financial instruments as of December 31, 2017 are as follows: December 31, 2017 Carrying Amount Estimated Fair Value Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) (Amounts In Thousands) Financial instrument assets: Cash and cash equivalents $ 154,353 $ 154,353 $ 154,353 $ — $ — Investment securities 300,160 300,160 — 300,160 — Loans held for sale 5,162 5,162 — 5,162 — Loans Agricultural 86,286 86,229 — — 86,229 Commercial and financial 213,795 212,244 — — 212,244 Real estate: Construction, 1 to 4 family residential 68,545 69,036 — — 69,036 Construction, land development and commercial 107,799 108,651 — — 108,651 Mortgage, farmland 211,617 211,947 — — 211,947 Mortgage, 1 to 4 family first liens 824,222 818,083 — — 818,083 Mortgage, 1 to 4 family junior liens 142,901 142,180 — — 142,180 Mortgage, multi-family 334,019 329,344 — — 329,344 Mortgage, commercial 358,287 353,796 — — 353,796 Loans to individuals 25,635 25,610 — — 25,610 Obligations of state and political subdivisions 57,165 55,066 — — 55,066 Accrued interest receivable 10,772 10,772 — 10,772 — Total financial instrument assets $ 2,900,718 $ 2,882,633 $ 154,353 $ 316,094 $ 2,412,186 Financial instrument liabilities: Deposits Noninterest-bearing deposits $ 363,817 $ 363,817 $ — $ 363,817 $ — Interest-bearing deposits 1,924,748 1,934,442 — 1,934,442 — Other borrowings — — — — — Federal Home Loan Bank borrowings 295,000 284,442 — 284,442 — Interest rate swaps 2,819 2,819 2,819 Accrued interest payable 1,290 1,290 — 1,290 — Total financial instrument liabilities $ 2,587,674 $ 2,586,810 $ — $ 2,586,810 $ — Face Amount Financial instrument with off-balance sheet risk: Loan commitments $ 380,877 $ — $ — $ — $ — Letters of credit 9,113 — — — — Total financial instrument liabilities with off-balance-sheet risk $ 389,990 $ — $ — $ — $ — (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. Fair value of financial instruments : FASB ASC 820, Fair Value Measurements and Disclosures (“ASC 820”) provides a single definition for fair value, a framework for measuring fair value and expanded disclosures concerning fair value. Fair value is defined under ASC 820 as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company determines the fair market value of its financial instruments based on the fair value hierarchy established in ASC 820. There are three levels of inputs that may be used to measure fair value as follows: Level 1 Quoted prices in active markets for identical assets or liabilities. Level 2 Observable inputs other than quoted prices included within Level 1. Observable inputs include the quoted prices for similar assets or liabilities in markets that are not active and inputs other than quoted prices that are observable for the asset or liability. Level 3 Unobservable inputs supported by little or no market activity for financial instruments. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. It is the Company’s policy to maximize the use of observable inputs and minimize the use of unobservable inputs when developing fair value measurements. The Company is required to use observable inputs, to the extent available, in the fair value estimation process unless that data results from forced liquidations or distressed sales. The following is a description of valuation methodologies used for assets and liabilities recorded at fair value and for estimating fair value for assets or liabilities not recorded at fair value. ASSETS Cash and cash equivalents : The carrying amounts reported in the consolidated balance sheets for cash and short-term instruments approximate their fair values (Level 1). Investment securities available for sale : Investment securities available for sale are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted prices, if available. If a quoted price is not available, the fair value is obtained from benchmarking the security against similar securities. All of the Company’s securities are considered Level 2. The pricing for investment securities is obtained from an independent source. There are no Level 1 or Level 3 investment securities owned by the Company. The Company obtains an understanding of the independent source’s valuation methodologies used to determine fair value by level of security. The Company validates assigned fair values on a sample basis using an additional third-party provider pricing service to determine if the fair value measurement is reasonable. Due to the nature of our investment portfolio, we do not expect significant and unusual fluctuations as fair value changes primarily relate to interest rate changes. No unusual fluctuations were identified during the nine months ended September 30, 2018 . If a fluctuation requiring investigation was identified, the Company would research the change with the independent source or other available information. Loans held for sale and Loans : ASU 2016-1, Financial Instruments -Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes. This update is effective for financial statement periods beginning after December 15, 2017. Therefore, the fair value presented herein may not be comparable to prior periods. Methodologies utilized for this financial statement period are as follows: •Income Approach: Fair value is determined based on a discounted cash flow analysis. The discounted cash flow analysis was based on the contractual maturity of the loan and market indications of rates, prepayment speeds, defaults and credit risk. •Asset Approach: Fair value is determined based on the estimated values of the underlying collateral or individual analysis of receipts. This provides a better indication of value than the contractual income streams as these loans are not performing or exhibit strong signs indicative of non-performance. Fair value has been estimated in accordance with ASC 820, Fair Value Measurements and Disclosures, and is intended to represent the price that would be received in an orderly transaction between market participants as of the measurement date. In general, fair value is based upon quoted market prices, where available. If such quoted market prices are not available, at least one significant assumption not observable in the market was utilized. These unobservable assumptions reflect estimates that market participants would use in pricing the asset or liability. Inputs to these valuation techniques are subjective in nature, involve uncertainties and require significant judgment and therefore cannot be determined with precision. Accordingly, the fair value estimates presented are not necessarily indicative of the amounts to be realized in a current market exchange. Loans are classified as Level 3. Foreclosed assets : The Company does not record foreclosed assets at fair value on a recurring basis. Foreclosed assets consist mainly of other real estate owned but may include other types of assets repossessed by the Company. Foreclosed assets are adjusted to the lower of carrying value or fair value less the cost of disposal. Fair value is generally based upon independent market prices or appraised values of the collateral, and may include a marketability discount as deemed necessary by management based on its experience with similar types of real estate. The value of foreclosed assets is evaluated periodically as a nonrecurring fair value adjustment. Foreclosed assets are classified as Level 3. Off-balance sheet instruments : Fair values for outstanding letters of credit are based on fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements and the counterparties' credit standing. The fair value of the outstanding letters of credit is not significant. Unfunded loan commitments are not valued since the loans are generally priced at market at the time of funding (Level 2). Accrued interest receivable : The fair value of accrued interest receivable equals the amount receivable due to the current nature of the amounts receivable (Level 2). Non-marketable equity investments : Non-marketable equity investments are recorded under the cost or equity method of accounting. There are generally restrictions on the sale and/or liquidation of these investments, including stock of the Federal Home Loan Bank. The carrying value of stock of the Federal Home Loan Bank approximates fair value (Level 2). LIABILITIES Deposit liabilities : Deposit liabilities are carried at historical cost. The fair value of demand deposits, savings accounts and certain money market account deposits is the amount payable on demand at the reporting date. The fair value of fixed maturity certificates of deposit is estimated using the rates currently offered for deposits of similar remaining maturities. If the fair value of the fixed maturity certificates of deposit is calculated at less than the carrying amount, the carrying value of these deposits is reported as the fair value (Level 2). Deposit liabilities are classified as Level 2 due to available prices for similar liabilities in the market. Other borrowings : Other borrowings are carried at historical cost and include federal funds purchased and securities sold under agreements to repurchase. The carrying amount is a reasonable estimate of fair value because of the relatively short time between the origination of the liability and its expected realization (Level 2). Other borrowings are classified as Level 2 due to available prices for similar liabilities in the market. Federal Home Loan Bank borrowings : Federal Home Loan Bank borrowings are recorded at historical cost. The fair values of the Company’s Federal Home Loan Bank borrowings are estimated using discounted cash flow analysis, based on the Company’s current incremental borrowing rates for similar types of borrowing arrangements (Level 2). Federal Home Loan Bank borrowings are classified as Level 2 due to available prices for similar liabilities in the market. Interest Rate Swap Agreements : The fair value is estimated using forward-looking interest rate curves and is calculated using discounted cash flows that are observable or that can be corroborated by observable market data (Level 2). Accrued interest payable : The fair value of accrued interest payable equals the amount payable due to the current nature of the amounts payable (Level 2). Assets and Liabilities Recorded at Fair Value on a Recurring Basis The table below represents the balances of assets and liabilities measured at fair value on a recurring basis: September 30, 2018 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Securities available for sale (Amounts In Thousands) U.S. Treasury $ — $ 82,353 $ — $ 82,353 State and political subdivisions — 175,216 — 175,216 Other securities (FHLB, FHLMC and FNMA) — 34,733 — 34,733 Derivative Financial Instruments Interest rate swaps $ — (932 ) $ — (932 ) Total $ — $ 291,370 $ — $ 291,370 December 31, 2017 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Securities available for sale (Amounts In Thousands) U.S. Treasury $ — $ 54,318 $ — $ 54,318 State and political subdivisions — 186,878 — 186,878 Other securities (FHLB, FHLMC and FNMA) — 43,959 — 43,959 Derivative Financial Instruments Interest rate swaps — (2,819 ) — (2,819 ) Total $ — $ 282,336 $ — $ 282,336 (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. There were no transfers between Levels 1, 2 or 3 during the nine months ended September 30, 2018 and the year ended December 31, 2017 . Assets and Liabilities Recorded at Fair Value on a Nonrecurring Basis The Company is required to measure certain assets at fair value on a nonrecurring basis in accordance with GAAP. These adjustments to fair value usually result from application of lower-of-cost-or-market accounting or write-downs of individual assets. The valuation methodologies used to measure these fair value adjustments are described above. The following tables present the Company’s assets that are measured at fair value on a nonrecurring basis. September 30, 2018 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Total Losses Total Losses (Amounts in Thousands) Loans (4) Agricultural $ — $ — $ 1,401 $ 1,401 $ — $ 63 Commercial and financial — — 2,039 2,039 (14 ) 122 Real Estate: — Construction, 1 to 4 family residential — — — — — — Construction, land development and commercial — — 701 701 — — Mortgage, farmland — — 3,964 3,964 — — Mortgage, 1 to 4 family first liens — — 6,232 6,232 169 313 Mortgage, 1 to 4 family junior liens — — 22 22 — 60 Mortgage, multi-family — — 6,180 6,180 — — Mortgage, commercial — — 1,502 1,502 186 258 Loans to individuals — — — — — — Foreclosed assets (5) — — — — — — Total $ — $ — $ 22,041 $ 22,041 $ 341 $ 816 (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. (4) Represents carrying value and related write-downs of loans for which adjustments are based on the value of the collateral. The carrying value of loans fully-charged off is zero . (5) Represents the fair value and related losses of foreclosed real estate and other collateral owned that were measured at fair value subsequent to their initial classification as foreclosed assets. Assets and Liabilities Recorded at Fair Value on a Nonrecurring Basis (continued) December 31, 2017 Year Ended December 31, 2017 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Total Losses (Amounts in Thousands) Loans (4) Agricultural $ — $ — $ 4,704 $ 4,704 $ 127 Commercial and financial — — 1,555 1,555 159 Real Estate: Construction, 1 to 4 family residential — — 729 729 — Construction, land development and commercial — — — — — Mortgage, farmland — — 7,190 7,190 — Mortgage, 1 to 4 family first liens — — 5,548 5,548 404 Mortgage, 1 to 4 family junior liens — — 25 25 88 Mortgage, multi-family — — 6,397 6,397 — Mortgage, commercial — — 1,063 1,063 111 Loans to individuals — — — — 20 Foreclosed assets (5) — — — — — Total $ — $ — $ 27,211 $ 27,211 $ 909 (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. (4) Represents carrying value and related write-downs of loans for which adjustments are based on the value of the collateral. The carrying value of loans fully-charged off is zero. (5) Represents the fair value and related losses of foreclosed real estate and other collateral owned that were measured at fair value subsequent to their initial classification as foreclosed assets.

Stock Repurchase Program

Stock Repurchase Program	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stock Repurchase Program	Stock Repurchase Program On July 26, 2005, the Company’s Board of Directors authorized a program to repurchase up to a total of 1,500,000 shares of the Company’s common stock (the “2005 Stock Repurchase Program”). The Company’s Board of Directors has authorized the 2005 Stock Repurchase Program through December 31, 2019. The Company expects the purchases pursuant to the 2005 Stock Repurchase Program to be made from time to time in private transactions at a price equal to the most recent quarterly independent appraisal of the shares of the Company’s common stock and with the Board reviewing the overall results of the 2005 Stock Repurchase Program on a quarterly basis. All purchases made pursuant to the 2005 Stock Repurchase Program since its inception have been made on that basis. The amount and timing of stock repurchases will be based on various factors, such as the Board’s assessment of the Company’s capital structure and liquidity, the amount of interest shown by shareholders in selling shares of stock to the Company at their appraised value, and applicable regulatory, legal and accounting factors. The Company has purchased 1,106,998 shares of its common stock in privately negotiated transactions from August 1, 2005 through September 30, 2018 . Of these 1,106,998 shares, 40,818 shares were purchased during the quarter ended September 30, 2018 , at an average price per share of $58.54 .

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Concentrations of credit risk : The Bank’s loans, commitments to extend credit, unused lines of credit and outstanding letters of credit have been granted to customers within the Bank's market area. Investments in securities issued by state and political subdivisions within the state of Iowa totaled approximately $76.18 million . The concentrations of credit by type of loan are set forth in Note 5 to the Consolidated Financial Statements. Outstanding letters of credit were granted primarily to commercial borrowers. Although the Bank has a diversified loan portfolio, a substantial portion of its debtors' ability to honor their contracts is dependent upon the economic conditions in Johnson, Linn and Washington Counties, Iowa. Contingencies : In the normal course of business, the Company and Bank are involved in various legal proceedings. While the ultimate outcome of such legal proceedings cannot be predicted with certainty, after reviewing pending and threatened litigation with counsel, management believes at this time that the outcome of such litigation will not have a material adverse effect on the Company's business, financial condition or results of operations. Financial instruments with off-balance sheet risk : The Bank is a party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit, credit card participations and standby letters of credit. These instruments involve, to varying degrees, elements of credit risk in excess of the amount recognized in the consolidated balance sheets. The Bank’s exposure to credit loss in the event of nonperformance by the other party to the financial instrument for commitments to extend credit, credit card participations and standby letters of credit is represented by the contractual amount of those instruments. The Bank uses the same credit policies in making commitments and conditional obligations as it does for on-balance sheet instruments. A summary of the Bank’s commitments at September 30, 2018 and December 31, 2017 is as follows: September 30, 2018 December 31, 2017 (Amounts In Thousands) Firm loan commitments and unused portion of lines of credit: Home equity loans $ 60,442 $ 55,171 Credit cards 52,882 49,235 Commercial, real estate and home construction 104,426 117,021 Commercial lines and real estate purchase loans 189,351 159,450 Outstanding letters of credit 7,841 9,113

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Federal income tax expense for the nine months ended September 30, 2018 and 2017 was computed using the consolidated effective federal tax rate. The Company also recognized income tax expense pertaining to state franchise taxes payable individually by the subsidiary bank. The Company files a consolidated tax return for federal purposes and separate tax returns for State of Iowa purposes. The tax years ended December 31, 2017 , 2016 , and 2015 remain subject to examination by the Internal Revenue Service. For state tax purposes, the tax years ended December 31, 2017 , 2016 , and 2015 remain open for examination. There were no material unrecognized tax benefits at September 30, 2018 and December 31, 2017 and therefore no interest or penalties on unrecognized tax benefits has been recorded. As of September 30, 2018 , the Company does not anticipate any significant increase in unrecognized tax benefits during the twelve-month period ending September 30, 2019. Income taxes as a percentage of income before taxes were 20.05% for the nine months ended September 30, 2018 and 30.48% for the same period in 2017 . On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cut and Jobs Act (the “Tax Act”). The Tax Act established new tax laws that reduced the U.S. federal corporate income tax rate from 35% to 21% in 2018.

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments In the normal course of business, the Bank may use derivative financial instruments to manage its interest rate risk. These instruments carry varying degrees of credit, interest rate and market or liquidity risks. Derivative instruments are recognized as either assets or liabilities in the accompanying financial statement and are measured at fair value. The Bank’s objectives are to add stability to its net interest margin and to manage its exposure to movements in interest rates. The contract or notional amount of a derivative is used to determine, along with the other terms of the derivative, the amount to be exchanged between the counterparties. The Bank is exposed to credit risk in the event of nonperformance by counterparties to financial instruments. The Bank minimizes this risk by entering into derivative contracts with large, stable financial institutions. The Bank has not experienced any losses from nonperformance by counterparties. The Bank monitors counterparty risk in accordance with the provisions of ASC 815. In addition, the Bank’s interest rate-related derivative instruments contain language outlining collateral pledging requirements for each counterparty. Collateral must be posted when the market value exceeds certain threshold limits which are determined by credit ratings of each counterparty. The Bank was required to pledge $0.93 million of collateral as of September 30, 2018 . Cash Flow Hedges: The Bank executed two forward-starting interest rate swap transactions on November 7, 2013. One of the interest rate swap transactions had an effective date of November 9, 2015, and an expiration date of November 9, 2020, effectively converting $25.00 million of variable rate debt to fixed rate debt. The other interest rate swap transaction had an effective date of November 7, 2016 and an expiration date of November 7, 2023, effectively converting $25.00 million of variable rate debt to fixed rate debt. For accounting purposes, these swap transactions are designated as a cash flow hedge of the changes in cash flows attributable to changes in three-month LIBOR, the benchmark interest rate being hedged, associated with the interest payments made on an amount of the Bank’s debt principal equal to the then-outstanding swap notional amount. At inception, the Bank asserted that the underlying principal balance would remain outstanding throughout the hedge transaction making it probable that sufficient LIBOR-based interest payments would exist through the maturity date of the swaps. The table below identifies the balance sheet category and fair values of the Bank’s derivative instruments designated as cash flow hedges as of September 30, 2018 and December 31, 2017 : Notional Amount Fair Value Balance Sheet Category Maturity (Amounts in Thousands) September 30, 2018 Interest rate swap $ 25,000 $ 26 Other Liabilities 11/9/2020 Interest rate swap 25,000 (958 ) Other Liabilities 11/7/2023 December 31, 2017 Interest rate swap $ 25,000 $ (582 ) Other Liabilities 11/9/2020 Interest rate swap 25,000 (2,237 ) Other Liabilities 11/7/2023 The table below identifies the gains and losses recognized on the Bank’s derivative instruments designated as cash flow hedges for the nine months ended September 30, 2018 and year ended December 31, 2017 : Effective Portion Ineffective Portion Recognized in OCI Reclassifed from AOCI into Income Recognized in Income on Derivatives Amount of Gain (Loss) Category Amount of Gain (Loss) Category Amount of Gain (Loss) (Amounts in Thousands) September 30, 2018 Interest rate swap $ 457 Interest Expense $ — Other Income $ — Interest rate swap 960 Interest Expense — Other Income — December 31, 2017 Interest rate swap $ 318 Interest Expense $ — Other Income $ — Interest rate swap 373 Interest Expense — Other Income —

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation: The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial reporting and with instructions for Form 10-Q and Regulation S-X. These financial statements include all adjustments (consisting of normal recurring accruals) which in the opinion of management are considered necessary for the fair presentation of the financial position and results of operations for the periods shown. Certain prior year amounts have been reclassified to conform to the current year presentation. The Company considers that it operates as one business segment, a commercial bank.
Revenue Recognition	Revenue Recognition Accounting Standards Codification ("ASC") 606, Revenue from Contracts with Customers ("ASC 606"), establishes principles for reporting information about the nature, amount, timing and uncertainty of revenue and cash flows arising from the Company’s contracts to provide goods or services to customers. The core principle requires an entity to recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration that it expects to be entitled to receive in exchange for those goods or services recognized as performance obligations are satisfied. The majority of the Company’s revenue-generating transactions are not subject to ASC 606, including revenue generated from financial instruments, such as loans, letters of credit and investment securities as these activities are not subject to the requirements of ASC 606. Interest income on loans and investment securities is recognized on the accrual method in accordance with written contracts. Descriptions of the Company’s revenue-generating activities that are within the scope of ASC 606 are the following: Service charges and fees on deposit accounts represent general service fees for monthly account maintenance and activity- or transaction-based fees and consist of transaction-based revenue which includes interchange income, time-based revenue (service period), item-based revenue or some other individual attribute-based revenue. Revenue is recognized when the Company’s performance obligation is completed which is generally monthly for account maintenance services or when a transaction has been completed (such as a wire transfer). Payment for such performance obligations are generally received at the time the performance obligations are satisfied. Trust income represents monthly fees due from wealth management customers as consideration for managing the customers' assets. Wealth management and trust services include custody of assets, investment management, fees for trust services and similar fiduciary activities. Revenue is recognized when our performance obligation is completed each month, which is generally the time that payment is received.
Effect of New Financial Accounting Standards	Effect of New Financial Accounting Standards: In May 2014, The FASB and International Accounting Standards Board (IASB) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The core principle of ASU 2014-09 is that a company should recognize revenue to depict the transfer of promised good or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. ASU 2014-09 is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. The adoption of ASU 2014-09 by the Company did not have a material impact on the recognition of revenue though did require additional disclosures on our material noninterest income streams discussed in revenue recognition above. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments - Overall (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities. ASU 2016-01 created Subtopic 321-10, Investments-Equity Securities which is applicable to all entities except those in industries that account for substantially all investments at fair value through earnings or the change in net assets. Under this new subtopic, equity securities are generally required to be measured at fair value with unrealized holding gains and losses reflected in net income. ASU 2016-01 is effective for annual periods and interim periods within those annual periods beginning after December 15, 2017. The Company adopted ASU 2016-01 for the period ending March 31, 2018. There was no material impact on the financial statements however it required a change in disclosure and related methodology located in Note 6 Fair Value Measurements. In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases . The ASU provides guidance requiring lessees to recognize right-of-use (ROU) assets and lease liabilities for all leases other than those that meet the definition of short-term leases. For short-term leases, lessees may elect an accounting policy by class of underlying asset under which these assets and liabilities are not recognized and lease payments are generally recognized over the lease term on a straight-line basis. Under this new ASU, lessees will recognize right-of use assets and lease liabilities for most leases currently accounted for as operating leases under generally accepted accounting principles. For public companies, ASU 2016-02 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Company is in the process of analyzing a comprehensive list of lease agreements. We expect to adopt the new standard on January 1, 2019 and use the effective date as our date of initial application. Consequently, financial information will not be updated and the disclosures required under the new standard will not be provided for dates and periods before January 1, 2019. The new standard provides a number of optional practical expedients in transition. We expect to elect the 'package of practical expedients', which permits us not to reassess under the new standard our prior conclusions about lease identification, lease classification and initial direct costs. We do not expect to elect the use-of-hindsight or the practical expedient pertaining to land easements; the latter not being applicable to us. We expect that this standard will not have a material effect on our financial statements. While we continue to assess all of the effects of adoption, we currently believe the most significant effects relate to the recognition of new ROU assets and lease liabilities on our balance sheet for our equipment and real estate operating leases. We do not expect a significant change in our leasing activities between now and adoption. On adoption, we currently expect to recognize additional operating liabilities ranging from $3 million to $3.5 million , with corresponding ROU assets of the same amount based on the present value of the remaining minimum rental payments under current leasing standards for existing operating leases. In March 2016, the FASB issued ASU No. 2016-04, Liabilities - Extinguishments of Liabilities (Subtopic 405-20), Recognition of Breakage for Certain Prepaid Stored-Value Products . ASU 2016-04 applies to all entities that offer certain prepaid stored - value products. The ASU provides guidance for the derecognition of financial liabilities related to the issuance of these products and aligns the recognition of breakage to current authoritative guidance. For public companies, ASU 2016-04 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. The Company adopted ASU 2016-04 for the period ending March 31, 2018. There was no material impact on the financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments (CECL). The ASU changes the way entities recognize impairment of financial assets by requiring immediate recognition of estimated credit losses expected to occur over the remaining life of many financial assets. Under the CECL model, we will be required to present certain financial assets carried at amortized cost, such as loans held for investment and held-to-maturity debt securities, at the net amount expected to be collected. The measurement of expected credit losses is to be based on information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. This measurement will take place at the time the financial asset is first added to the balance sheet and periodically thereafter. This differs significantly from the "incurred loss" model required under current GAAP, which delays recognition until it is probable a loss has been incurred. Accordingly, we expect that the adoption of the CECL model will materially affect how we determine our allowance for loan losses and could require us to significantly increase our allowance. For public companies, ASU 2016-13 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019, early adoption is permitted for the fiscal year beginning after December 15, 2018. The Company has implemented a software solution to assist in the analysis of historical loan data to determine the CECL model that will be implemented and is in the process of validating the historical loan data in the software solution. The Company anticipates running parallel calculations of the "incurred loss" and CECL models for the quarter ending March 31, 2019. We expect to recognize a one-time cumulative-effect adjustment to our allowance for loan losses as of the beginning of the first reporting period in which the new standard is adopted. The amount of the one-time cumulative-effect adjustment has not yet been determined. In January 2017, the FASB issued ASU No. 2017-03, Accounting Changes and Error Corrections (Topic 250) and Investments - Equity Method and Joint Ventures (Topic 323), Amendments to SEC Paragraphs Pursuant to Staff Announcements at the September 22, 2016 and November 17, 2016 EITF Meetings. This ASU adds an SEC paragraph and amends other Topics pursuant to an SEC staff Announcement made at the September 22, 2016 Emerging Issues Task Force (EITF) meeting. The SEC paragraph applies to ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606); ASU No. 2016-02, Leases (Topic 842); and ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU provides that a company should evaluate ASUs that have not yet been adopted to determine the appropriate financial statement disclosures about the potential material effects of those ASUs on the financial statements when adopted. If the company does not know or cannot reasonably estimate the impact that adoption of the ASUs referenced in this announcement is expected to have on the financial statements, then in addition to making a statement to that effect, the company should consider additional qualitative financial statement disclosures to assist the reader in assessing the significance of the impact that the standard will have on the financial statements of the company when adopted. Additional qualitative disclosures should include a description of the effect of the accounting policies that the company expects to apply and a comparison to the company's current accounting policies. Also, the company should describe the status of its process to implement the new standards and the significant implementation matters yet to be addressed. In January 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 250), Simplifying the Test for Goodwill Impairment. The ASU simplifies the goodwill impairment test by requiring a company to perform its annual or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge should be recognized when the carrying amount exceeds fair value. For public companies, ASU 2017-04 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The adoption of ASU No. 2017-04 by the Company is not expected to have a material impact. In August 2017, the FASB issued ASU No. 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities. This ASU requires companies to change the recognition and presentation of the effects of hedge accounting by eliminating the requirement to separately measure and report hedge ineffectiveness and requiring companies to present all of the elements of hedge accounting that affect earnings in the same income statement line as the hedged item. Furthermore, the standard eases the requirements for effectiveness testing, hedge documentation and applying the critical terms match method and introduces new alternatives that will permit companies to reduce the risk of material error corrections if they misapply the shortcut method. For public companies, ASU 2017-12 is effective for fiscal years, and interim periods within those fiscal years beginning after December 15, 2018. The adoption of ASU 2017-12 by the Company is not expected to have a material impact. In February 2018, the FASB issued ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220), Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. This ASU allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act. ASU 2018-02 is effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. The Company adopted ASU 2018-02 for the period ending March 31, 2018 and elected the specific identification method accounting policy. There was a $0.53 million reclassification recorded in stockholders' equity. In June 2018, the FASB issued ASU No. 2018-07, Compensation - Stock Compensation (Topic 718), Improvements to Nonemployee Share-Based Payment Accounting . The amendments in this ASU expand the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from nonemployees. ASU 2018-07 is effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. The adoption of ASU 2018-07 by the Company is not expected to have a material impact. In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement . The amendments in this ASU modify the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement, including removal of the requirement to disclose the valuation processes for Level 3 fair value measurements and the additional requirement to disclose the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. ASU 2018-13 is effective for all entities for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. The amendments on changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements, and the narrative description of measurement uncertainty should be applied prospectively for only the most recent interim or annual period presented in the initial fiscal year of adoption. All other amendments should be applied retrospectively to all periods presented upon their effective date. Early adoption is permitted upon issuance of this ASU. An entity is permitted to early adopt any removed or modified disclosures upon issuance of this ASU and delay adoption of the additional disclosures until their effective date. The adoption of ASU 2018-13 by the Company is not expected to have a material impact. In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40), Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangements That Is a Service Contract. The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal-use software license). ASU 2018-15 is effective for public business entities for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption of the amendments in this ASU is permitted, including adoption in any interim period, for all entities. The amendments in this ASU should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. The Company is in the process of evaluating the impact of this ASU on the financial statements.
Earnings Per Share	Earnings Per Share Basic earnings per share is computed using the weighted average number of actual common shares outstanding during the period. Diluted earnings per share reflects the potential dilution that would occur from the exercise of common stock options outstanding. ESOP shares are considered outstanding for this calculation unless unearned.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted earnings per share	The computation of basic and diluted earnings per share for the periods presented is as follows: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Common shares outstanding at the beginning of the period 9,373,666 9,329,514 9,335,154 9,264,227 Weighted average number of net shares (redeemed) issued (22,223 ) (4,596 ) 40,123 64,144 Weighted average shares outstanding (basic) 9,351,443 9,324,918 9,375,277 9,328,371 Weighted average of potential dilutive shares attributable to stock options granted, computed under the treasury stock method 4,245 3,559 4,067 4,874 Weighted average number of shares (diluted) 9,355,688 9,328,477 9,379,344 9,333,245 Net income (In thousands) $ 10,050 $ 8,552 $ 30,971 $ 23,883 Earnings per share: Basic $ 1.07 $ 0.92 $ 3.30 $ 2.56 Diluted $ 1.07 $ 0.92 $ 3.30 $ 2.56

Other Comprehensive Income (L_2

Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Components of accumulated other comprehensive income (AOCI)	The following table summarizes the balances of each component of accumulated other comprehensive income (AOCI), included in stockholders’ equity, at September 30, 2018 and December 31, 2017 : September 30, December 31, 2017 (amounts in thousands) Net unrealized loss on available-for-sale securities $ (4,990 ) $ (1,141 ) Net unrealized loss on derivatives used for cash flow hedges (932 ) (2,819 ) Tax effect $ 1,478 $ 1,514 Net-of-tax amount $ (4,444 ) $ (2,446 )

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 2018
Investments, Debt and Equity Securities [Abstract]
Carrying values of investment securities	The carrying values of investment securities at September 30, 2018 and December 31, 2017 are summarized in the following table (dollars in thousands): September 30, 2018 December 31, 2017 Amount Percent Amount Percent Securities available for sale U.S. Treasury $ 82,353 28.18 % $ 54,318 19.05 % Other securities (FHLB, FHLMC and FNMA) 34,733 11.88 43,959 15.42 State and political subdivisions 175,216 59.94 186,878 65.53 Total securities available for sale $ 292,302 100.00 % $ 285,155 100.00 %
Carrying amount of available-for-sale securities and approximate fair values	The carrying amount of available-for-sale securities and their approximate fair values were as follows as of September 30, 2018 and December 31, 2017 (in thousands): Amortized Cost Gross Unrealized Gains Gross Unrealized (Losses) Estimated Fair Value September 30, 2018: U.S. Treasury $ 83,949 $ — $ (1,596 ) $ 82,353 Other securities (FHLB, FHLMC and FNMA) 35,398 1 (666 ) 34,733 State and political subdivisions 177,945 129 (2,858 ) 175,216 Total $ 297,292 $ 130 $ (5,120 ) $ 292,302 December 31, 2017: U.S. Treasury $ 54,696 $ — $ (378 ) $ 54,318 Other securities (FHLB, FHLMC and FNMA) 44,470 1 (512 ) 43,959 State and political subdivisions 187,130 722 (974 ) 186,878 Total $ 286,296 $ 723 $ (1,864 ) $ 285,155
Available-for-sale securities classified as per contractual maturities	The amortized cost and estimated fair value of available-for-sale securities classified according to their contractual maturities at September 30, 2018 , were as follows (in thousands): Amortized Cost Fair Value Due in one year or less $ 41,457 $ 41,340 Due after one year through five years 180,463 177,642 Due after five years through ten years 74,811 72,759 Due over ten years 561 561 Total $ 297,292 $ 292,302
Available-for-sale securities, continuous unrealized loss position, fair value	The following table shows the fair value, gross unrealized losses and the percentage of fair value represented by gross unrealized losses of applicable investment securities owned by the Company, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at September 30, 2018 and December 31, 2017 (in thousands): Less than 12 months 12 months or more Total September 30, 2018 # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % U.S. Treasury 24 $ 58,023 $ (987 ) 1.70 % 10 $ 24,330 $ (609 ) 2.50 % 34 $ 82,353 $ (1,596 ) 1.94 % Other securities (FHLB, FHLMC and FNMA) 1 2,494 (9 ) 0.36 13 32,239 (657 ) 2.04 14 34,733 (666 ) 1.92 State and political subdivisions 377 94,638 (1,490 ) 1.57 142 33,670 (1,368 ) 4.06 519 128,308 (2,858 ) 2.23 Total temporarily impaired securities 402 $ 155,155 $ (2,486 ) 1.60 % 165 $ 90,239 $ (2,634 ) 2.92 % 567 $ 245,394 $ (5,120 ) 2.09 % Less than 12 months 12 months or more Total December 31, 2017 # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % # Fair Value Unrealized Loss % U.S. Treasury 22 $ 54,318 $ (378 ) 0.70 % — $ — $ — — % 22 $ 54,318 $ (378 ) 0.70 % Other securities (FHLB, FHLMC and FNMA) 9 21,411 (83 ) 0.39 9 22,547 (429 ) 1.90 18 43,958 (512 ) 1.16 State and political subdivisions 241 58,803 (573 ) 0.97 65 14,944 (401 ) 2.68 306 73,747 (974 ) 1.32 Total temporarily impaired securities 272 $ 134,532 $ (1,034 ) 0.77 % 74 $ 37,491 $ (830 ) 2.21 % 346 $ 172,023 $ (1,864 ) 1.08 %

Loans (Tables)

Loans (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Schedule of classes of loans	Classes of loans are as follows: September 30, December 31, (Amounts In Thousands) Agricultural $ 79,155 $ 88,580 Commercial and financial 214,681 218,632 Real estate: Construction, 1 to 4 family residential 65,932 69,738 Construction, land development and commercial 106,012 109,595 Mortgage, farmland 230,032 215,286 Mortgage, 1 to 4 family first liens 899,937 831,591 Mortgage, 1 to 4 family junior liens 149,312 144,200 Mortgage, multi-family 347,660 336,810 Mortgage, commercial 381,966 361,196 Loans to individuals 27,946 26,417 Obligations of state and political subdivisions 53,149 57,626 $ 2,555,782 $ 2,459,671 Net unamortized fees and costs 948 894 $ 2,556,730 $ 2,460,565 Less allowance for loan losses 31,010 29,400 $ 2,525,720 $ 2,431,165
Schedule of changes in allowance for loan losses	Changes in the allowance for loan losses, the allowance for loan losses applicable to impaired loans and the related loan balance of impaired loans for the three and nine months ended September 30, 2018 were as follows: Three Months Ended September 30, 2018 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,071 $ 5,040 $ 3,054 $ 3,475 $ 8,902 $ 5,697 $ 1,271 $ 29,510 Charge-offs (68 ) (241 ) — — (280 ) (107 ) (197 ) (893 ) Recoveries 74 415 2 10 187 80 32 800 Provision (47 ) (133 ) (188 ) 50 1,756 193 (38 ) 1,593 Ending balance $ 2,030 $ 5,081 $ 2,868 $ 3,535 $ 10,565 $ 5,863 $ 1,068 $ 31,010 Nine Months Ended September 30, 2018 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,294 $ 4,837 $ 2,989 $ 3,669 $ 8,668 $ 5,700 $ 1,243 $ 29,400 Charge-offs (72 ) (447 ) — — (607 ) (161 ) (420 ) (1,707 ) Recoveries 102 856 147 29 433 97 114 1,778 Provision (294 ) (165 ) (268 ) (163 ) 2,071 227 131 1,539 Ending balance $ 2,030 $ 5,081 $ 2,868 $ 3,535 $ 10,565 $ 5,863 $ 1,068 $ 31,010 Ending balance, individually evaluated for impairment $ 118 $ 1,165 $ 3 $ — $ 91 $ 40 $ 48 $ 1,465 Ending balance, collectively evaluated for impairment $ 1,912 $ 3,916 $ 2,865 $ 3,535 $ 10,474 $ 5,823 $ 1,020 $ 29,545 Loans: Ending balance $ 79,155 $ 214,681 $ 171,944 $ 230,032 $ 1,049,249 $ 729,626 $ 81,095 $ 2,555,782 Ending balance, individually evaluated for impairment $ 2,342 $ 3,288 $ 927 $ 3,729 $ 6,728 $ 8,217 $ 48 $ 25,279 Ending balance, collectively evaluated for impairment $ 76,813 $ 211,393 $ 171,017 $ 226,303 $ 1,042,521 $ 721,409 $ 81,047 $ 2,530,503 Changes in the allowance for loan losses for the three and nine months ended September 30, 2017 were as follows: Three Months Ended September 30, 2017 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,341 $ 4,586 $ 3,165 $ 4,009 $ 8,340 $ 5,414 $ 1,095 $ 28,950 Charge-offs (27 ) (21 ) — (3 ) (55 ) (86 ) (113 ) (305 ) Recoveries 56 219 33 — 203 7 57 575 Provision 92 (43 ) (182 ) 2 98 107 56 130 Ending balance $ 2,462 $ 4,741 $ 3,016 $ 4,008 $ 8,586 $ 5,442 $ 1,095 $ 29,350 Nine Months Ended September 30, 2017 Agricultural Commercial and Financial Real Estate: Construction and land development Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family Real Estate: Mortgage, multi- family and commercial Other Total (Amounts In Thousands) Allowance for loan losses: Beginning balance $ 2,947 $ 4,531 $ 2,890 $ 3,417 $ 7,677 $ 4,045 $ 1,023 $ 26,530 Charge-offs (66 ) (478 ) (114 ) (3 ) (263 ) (130 ) (410 ) (1,464 ) Recoveries 123 882 443 — 570 236 203 2,457 Provision (542 ) (194 ) (203 ) 594 602 1,291 279 1,827 Ending balance $ 2,462 $ 4,741 $ 3,016 $ 4,008 $ 8,586 $ 5,442 $ 1,095 $ 29,350 Ending balance, individually evaluated for impairment $ 653 $ 913 $ 46 $ 784 $ 110 $ 409 $ 85 $ 3,000 Ending balance, collectively evaluated for impairment $ 1,809 $ 3,828 $ 2,970 $ 3,224 $ 8,476 $ 5,033 $ 1,010 $ 26,350 Loans: Ending balance $ 76,484 $ 214,199 $ 180,574 $ 208,982 $ 960,800 $ 694,771 $ 84,084 $ 2,419,894 Ending balance, individually evaluated for impairment $ 6,181 $ 2,985 $ 1,161 $ 8,179 $ 7,097 $ 8,097 $ 85 $ 33,785 Ending balance, collectively evaluated for impairment $ 70,303 $ 211,214 $ 179,413 $ 200,803 $ 953,703 $ 686,674 $ 83,999 $ 2,386,109
Schedule of credit quality indicators by type of loans	The following table presents the credit quality indicators by type of loans in each category as of September 30, 2018 and December 31, 2017 , respectively (amounts in thousands): Agricultural Commercial and Financial Real Estate: Construction, 1 to 4 family residential Real Estate: Construction, land development and commercial September 30, 2018 Grade: Excellent $ 2,466 $ 2,858 $ — $ 393 Good 13,521 46,227 11,782 22,648 Satisfactory 37,824 118,659 39,457 57,043 Monitor 19,630 33,612 13,516 24,687 Special Mention 901 7,095 782 178 Substandard 4,813 6,230 395 1,063 Total $ 79,155 $ 214,681 $ 65,932 $ 106,012 Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family first liens Real Estate: Mortgage, 1 to 4 family junior liens Real Estate: Mortgage, multi- family September 30, 2018 Grade: Excellent $ 3,700 $ 2,360 $ 524 $ 22,139 Good 52,301 33,045 3,931 70,444 Satisfactory 123,898 741,877 136,420 176,519 Monitor 36,890 91,612 4,930 59,380 Special Mention 3,983 11,031 1,549 12,910 Substandard 9,260 20,012 1,958 6,268 Total $ 230,032 $ 899,937 $ 149,312 $ 347,660 Real Estate: Mortgage, commercial Loans to individuals Obligations of state and political subdivisions Total September 30, 2018 Grade: Excellent $ 34,798 $ — $ 8,329 $ 77,567 Good 92,947 119 15,623 362,588 Satisfactory 181,337 26,800 18,522 1,658,356 Monitor 58,165 705 10,675 353,802 Special Mention 10,842 206 — 49,477 Substandard 3,877 116 — 53,992 Total $ 381,966 $ 27,946 $ 53,149 $ 2,555,782 Agricultural Commercial and Financial Real Estate: Construction, 1 to 4 family residential Real Estate: Construction, land development and commercial December 31, 2017 Grade: Excellent $ 2,585 $ 10,264 $ — $ 2,548 Good 15,755 51,620 4,710 27,296 Satisfactory 40,886 116,375 47,995 35,749 Monitor 17,009 29,392 15,188 39,760 Special Mention 6,898 5,576 1,845 3,358 Substandard 5,447 5,405 — 884 Total $ 88,580 $ 218,632 $ 69,738 $ 109,595 Real Estate: Mortgage, farmland Real Estate: Mortgage, 1 to 4 family first liens Real Estate: Mortgage, 1 to 4 family junior liens Real Estate: Mortgage, multi- family December 31, 2017 Grade: Excellent $ 4,751 $ 2,392 $ 489 $ 16,564 Good 54,409 30,094 4,527 75,768 Satisfactory 109,724 689,645 130,451 195,652 Monitor 32,655 76,766 4,881 42,373 Special Mention 5,306 12,072 1,834 — Substandard 8,441 20,622 2,018 6,453 Total $ 215,286 $ 831,591 $ 144,200 $ 336,810 Real Estate: Mortgage, commercial Loans to individuals Obligations of state and political subdivisions Total December 31, 2017 Grade: Excellent $ 30,355 $ 1 $ 8,794 $ 78,743 Good 98,434 118 30,607 393,338 Satisfactory 179,417 25,445 14,693 1,586,032 Monitor 43,786 500 3,532 305,842 Special Mention 6,303 182 — 43,374 Substandard 2,901 171 — 52,342 Total $ 361,196 $ 26,417 $ 57,626 $ 2,459,671
Schedule of past due loans	Past due loans as of September 30, 2018 and December 31, 2017 were as follows: 30 - 59 Days Past Due 60 - 89 Days Past Due 90 Days or More Past Due Total Past Due Current Total Loans Receivable Accruing Loans Past Due 90 Days or More (Amounts In Thousands) September 30, 2018 Agricultural $ 474 $ 84 $ 158 $ 716 $ 78,439 $ 79,155 $ — Commercial and financial 991 545 — 1,536 213,145 214,681 — Real estate: Construction, 1 to 4 family residential 566 437 — 1,003 64,929 65,932 — Construction, land development and commercial 458 — — 458 105,554 106,012 — Mortgage, farmland 240 751 — 991 229,041 230,032 — Mortgage, 1 to 4 family first liens 780 2,225 2,604 5,609 894,328 899,937 338 Mortgage, 1 to 4 family junior liens 59 88 — 147 149,165 149,312 — Mortgage, multi-family — 152 — 152 347,508 347,660 — Mortgage, commercial 135 349 — 484 381,482 381,966 — Loans to individuals 149 53 1 203 27,743 27,946 — Obligations of state and political subdivisions — — — — 53,149 53,149 — $ 3,852 $ 4,684 $ 2,763 $ 11,299 $ 2,544,483 $ 2,555,782 $ 338 December 31, 2017 Agricultural $ 324 $ — $ 269 $ 593 $ 87,987 $ 88,580 $ — Commercial and financial 447 20 93 560 218,072 218,632 — Real estate: Construction, 1 to 4 family residential — — — — 69,738 69,738 — Construction, land development and commercial 246 — — 246 $ 109,349 109,595 — Mortgage, farmland 269 — — 269 215,017 215,286 — Mortgage, 1 to 4 family first liens 5,143 1,750 2,939 9,832 $ 821,759 831,591 971 Mortgage, 1 to 4 family junior liens 579 116 — 695 143,505 144,200 — Mortgage, multi-family — — — — $ 336,810 336,810 — Mortgage, commercial 307 178 16 501 360,695 361,196 — Loans to individuals 206 55 6 267 $ 26,150 26,417 — Obligations of state and political subdivisions — — — — 57,626 57,626 — $ 7,521 $ 2,119 $ 3,323 $ 12,963 $ 2,446,708 $ 2,459,671 $ 971
Schedule of impaired loan information	Certain impaired loan information by loan type at September 30, 2018 and December 31, 2017 , was as follows: September 30, 2018 December 31, 2017 Non-accrual loans (1) Accruing loans past due 90 days or more TDR loans Non- accrual loans (1) Accruing loans past due 90 days or more TDR loans (Amounts In Thousands) (Amounts In Thousands) Agricultural $ 1,401 $ — $ 72 $ 1,651 $ — $ 2,309 Commercial and financial 489 — 1,845 825 — 1,943 Real estate: Construction, 1 to 4 family residential — — — — — — Construction, land development and commercial — — 330 — — 339 Mortgage, farmland 1,167 — 3,313 1,391 — 1,451 Mortgage, 1 to 4 family first liens 5,064 338 1,302 4,407 971 1,357 Mortgage, 1 to 4 family junior liens — — 25 7 — 25 Mortgage, multi-family 152 — — 218 — — Mortgage, commercial 1,049 — 948 597 — 1,046 $ 9,322 $ 338 $ 7,835 $ 9,096 $ 971 $ 8,470 (1) There were $4.15 million and $3.62 million of TDR loans included within nonaccrual loans as of September 30, 2018 and December 31, 2017 , respectively.
Schedule of information for TDR loans	Below is a summary of information for TDR loans as of September 30, 2018 and December 31, 2017 : September 30, 2018 December 31, 2017 Number of contracts Recorded investment Commitments outstanding Number of contracts Recorded investment Commitments outstanding (Amounts In Thousands) (Amounts In Thousands) Agricultural 4 $ 1,306 $ 582 9 $ 3,628 $ 321 Commercial and financial 13 2,269 85 14 2,575 169 Real estate: Construction, 1 to 4 family residential — — — — — 16 Construction, land development and commercial 2 330 — 2 339 — Mortgage, farmland 8 4,407 — 7 2,761 — Mortgage, 1 to 4 family first liens 17 1,760 — 13 1,442 — Mortgage, 1 to 4 family junior liens 1 25 — 1 25 24 Mortgage, multi-family — — — — — — Mortgage, commercial 9 1,885 — 8 1,324 — Loans to individuals — — — — — — 54 $ 11,982 $ 667 54 $ 12,094 $ 530 The following is a summary of TDR loans that were modified during the three and nine months ended September 30, 2018 : Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Number of contracts Pre-modification recorded investment Post-modification recorded investment Number of contracts Pre-modification recorded investment Post-modification recorded investment (Amounts In Thousands) (Amounts In Thousands) Agricultural — $ — $ — — $ — $ — Commercial and financial 2 80 80 4 541 541 Real estate: Construction, 1 to 4 family residential — — — — — — Construction, land development and commercial — — — — — — Mortgage, farmland — — — 2 4,944 4,944 Mortgage, 1 to 4 family first lien — — — 6 627 627 Mortgage, 1 to 4 family junior liens — — — — — — Mortgage, multi-family — — — — — — Mortgage, commercial 1 578 578 2 852 852 3 $ 658 $ 658 14 $ 6,964 $ 6,964
Schedule of impaired loans	Information regarding impaired loans as of and for the three and nine months ended September 30, 2018 is as follows: September 30, 2018 Three Months Ended Nine Months Ended September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized With no related allowance recorded: (Amounts In Thousands) Agricultural $ 2,224 $ 2,525 $ — $ 2,850 $ 15 $ 1,905 $ 14 Commercial and financial 1,515 2,208 — 1,633 14 1,781 44 Real estate: Construction, 1 to 4 family residential 111 148 — 111 1 113 4 Construction, land development and commercial 330 347 — 331 3 334 10 Mortgage, farmland 3,729 4,147 — 3,744 32 3,126 67 Mortgage, 1 to 4 family first liens 5,562 7,162 — 5,708 10 5,827 29 Mortgage, 1 to 4 family junior liens — 256 — — — — — Mortgage, multi-family 152 218 — 153 — 156 — Mortgage, commercial 1,922 2,510 — 2,041 10 1,965 32 Loans to individuals — 14 — — — — — $ 15,545 $ 19,535 $ — $ 16,571 $ 85 $ 15,207 $ 200 With an allowance recorded: Agricultural $ 118 $ 118 $ 118 $ 118 $ 2 $ 184 $ 8 Commercial and financial 1,773 1,873 1,165 1,821 22 2,028 74 Real estate: Construction, 1 to 4 family residential — — — — — — — Construction, land development and commercial 486 486 3 492 6 495 17 Mortgage, farmland — — — — — — — Mortgage, 1 to 4 family first liens 1,142 1,198 88 1,147 10 1,169 30 Mortgage, 1 to 4 family junior liens 24 24 3 25 — 25 1 Mortgage, multi-family 6,067 6,067 39 6,083 69 6,123 207 Mortgage, commercial 76 76 1 76 1 77 3 Loans to individuals 48 48 48 54 2 66 6 $ 9,734 $ 9,890 $ 1,465 $ 9,816 $ 112 $ 10,167 $ 346 Total: Agricultural $ 2,342 $ 2,643 $ 118 $ 2,968 $ 17 $ 2,089 $ 22 Commercial and financial 3,288 4,081 1,165 3,454 36 3,809 118 Real estate: Construction, 1 to 4 family residential 111 148 — 111 1 113 4 Construction, land development and commercial 816 833 3 823 9 829 27 Mortgage, farmland 3,729 4,147 — 3,744 32 3,126 67 Mortgage, 1 to 4 family first liens 6,704 8,360 88 6,855 20 6,996 59 Mortgage, 1 to 4 family junior liens 24 280 3 25 — 25 1 Mortgage, multi-family 6,219 6,285 39 6,236 69 6,279 207 Mortgage, commercial 1,998 2,586 1 2,117 11 2,042 35 Loans to individuals 48 62 48 54 2 66 6 $ 25,279 $ 29,425 $ 1,465 $ 26,387 $ 197 $ 25,374 $ 546 Information regarding impaired loans as of December 31, 2017 is as follows: Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded: (Amounts In Thousands) Agricultural $ 1,822 $ 2,193 $ — Commercial and financial 1,725 2,487 — Real estate: Construction, 1 to 4 family residential 114 150 — Construction, land development and commercial 338 371 — Mortgage, farmland 2,523 2,902 — Mortgage, 1 to 4 family first liens 6,045 7,507 — Mortgage, 1 to 4 family junior liens 7 482 — Mortgage, multi-family 218 355 — Mortgage, commercial 1,564 2,274 — Loans to individuals — 14 — $ 14,356 $ 18,735 $ — With an allowance recorded: Agricultural $ 3,094 $ 3,149 $ 133 Commercial and financial 1,043 1,043 1,018 Real estate: Construction, 1 to 4 family residential — — — Construction, land development and commercial 505 505 39 Mortgage, farmland 5,439 5,439 238 Mortgage, 1 to 4 family first liens 577 593 63 Mortgage, 1 to 4 family junior liens 25 25 3 Mortgage, multi-family 6,179 6,179 480 Mortgage, commercial 79 79 2 Loans to individuals 190 190 190 $ 17,131 $ 17,202 $ 2,166 Total: Agricultural $ 4,916 $ 5,342 $ 133 Commercial and financial 2,768 3,530 1,018 Real estate: Construction, 1 to 4 family residential 114 150 — Construction, land development and commercial 843 876 39 Mortgage, farmland 7,962 8,341 238 Mortgage, 1 to 4 family first liens 6,622 8,100 63 Mortgage, 1 to 4 family junior liens 32 507 3 Mortgage, multi-family 6,397 6,534 480 Mortgage, commercial 1,643 2,353 2 Loans to individuals 190 204 190 $ 31,487 $ 35,937 $ 2,166

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Carrying value and estimated fair values of entity's financial instruments	The carrying value and estimated fair values of the Company's financial instruments as of September 30, 2018 are as follows: September 30, 2018 Carrying Amount Estimated Fair Value Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) (Amounts In Thousands) Financial instrument assets: Cash and cash equivalents $ 192,723 $ 192,723 $ 192,723 $ — $ — Investment securities 304,474 304,474 — 304,474 — Loans held for sale 3,403 3,403 — — 3,403 Loans Agricultural 77,125 79,007 — — 79,007 Commercial and financial 209,600 210,339 — — 210,339 Real estate: Construction, 1 to 4 family residential 64,755 65,949 — — 65,949 Construction, land development and commercial 104,321 102,867 — — 102,867 Mortgage, farmland 226,497 227,368 — — 227,368 Mortgage, 1 to 4 family first liens 891,649 867,383 — — 867,383 Mortgage, 1 to 4 family junior liens 147,983 143,265 — — 143,265 Mortgage, multi-family 344,900 336,147 — — 336,147 Mortgage, commercial 378,863 369,365 — — 369,365 Loans to individuals 27,303 27,765 — — 27,765 Obligations of state and political subdivisions 52,724 51,762 — — 51,762 Accrued interest receivable 12,710 12,710 — 12,710 — Total financial instrument assets $ 3,039,030 $ 2,994,527 $ 192,723 $ 317,184 $ 2,484,620 Financial instrument liabilities Deposits Noninterest-bearing deposits $ 374,927 $ 374,927 $ — $ 374,927 $ — Interest-bearing deposits 2,113,825 2,122,255 — 2,122,255 — Other borrowings — — — — — Federal Home Loan Bank borrowings 215,000 207,705 — 207,705 — Interest rate swaps 932 932 — 932 — Accrued interest payable 1,708 1,708 — 1,708 — Total financial instrument liabilities $ 2,706,392 $ 2,707,527 $ — $ 2,707,527 $ — Face Amount Financial instrument with off-balance sheet risk: Loan commitments $ 407,101 $ — $ — $ — $ — Letters of credit 7,841 — — — — Total financial instrument liabilities with off-balance-sheet risk $ 414,942 $ — $ — $ — $ — (1) Considered Level 1 under Accounting Standards Codification (“ASC”) Topic 820, Fair Value Measurements and Disclosures (“ASC 820”). (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. The carrying value and estimated fair values of the Company's financial instruments as of December 31, 2017 are as follows: December 31, 2017 Carrying Amount Estimated Fair Value Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) (Amounts In Thousands) Financial instrument assets: Cash and cash equivalents $ 154,353 $ 154,353 $ 154,353 $ — $ — Investment securities 300,160 300,160 — 300,160 — Loans held for sale 5,162 5,162 — 5,162 — Loans Agricultural 86,286 86,229 — — 86,229 Commercial and financial 213,795 212,244 — — 212,244 Real estate: Construction, 1 to 4 family residential 68,545 69,036 — — 69,036 Construction, land development and commercial 107,799 108,651 — — 108,651 Mortgage, farmland 211,617 211,947 — — 211,947 Mortgage, 1 to 4 family first liens 824,222 818,083 — — 818,083 Mortgage, 1 to 4 family junior liens 142,901 142,180 — — 142,180 Mortgage, multi-family 334,019 329,344 — — 329,344 Mortgage, commercial 358,287 353,796 — — 353,796 Loans to individuals 25,635 25,610 — — 25,610 Obligations of state and political subdivisions 57,165 55,066 — — 55,066 Accrued interest receivable 10,772 10,772 — 10,772 — Total financial instrument assets $ 2,900,718 $ 2,882,633 $ 154,353 $ 316,094 $ 2,412,186 Financial instrument liabilities: Deposits Noninterest-bearing deposits $ 363,817 $ 363,817 $ — $ 363,817 $ — Interest-bearing deposits 1,924,748 1,934,442 — 1,934,442 — Other borrowings — — — — — Federal Home Loan Bank borrowings 295,000 284,442 — 284,442 — Interest rate swaps 2,819 2,819 2,819 Accrued interest payable 1,290 1,290 — 1,290 — Total financial instrument liabilities $ 2,587,674 $ 2,586,810 $ — $ 2,586,810 $ — Face Amount Financial instrument with off-balance sheet risk: Loan commitments $ 380,877 $ — $ — $ — $ — Letters of credit 9,113 — — — — Total financial instrument liabilities with off-balance-sheet risk $ 389,990 $ — $ — $ — $ — (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market.
Schedule of assets and liabilities measured at fair value on a recurring basis	The table below represents the balances of assets and liabilities measured at fair value on a recurring basis: September 30, 2018 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Securities available for sale (Amounts In Thousands) U.S. Treasury $ — $ 82,353 $ — $ 82,353 State and political subdivisions — 175,216 — 175,216 Other securities (FHLB, FHLMC and FNMA) — 34,733 — 34,733 Derivative Financial Instruments Interest rate swaps $ — (932 ) $ — (932 ) Total $ — $ 291,370 $ — $ 291,370 December 31, 2017 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Securities available for sale (Amounts In Thousands) U.S. Treasury $ — $ 54,318 $ — $ 54,318 State and political subdivisions — 186,878 — 186,878 Other securities (FHLB, FHLMC and FNMA) — 43,959 — 43,959 Derivative Financial Instruments Interest rate swaps — (2,819 ) — (2,819 ) Total $ — $ 282,336 $ — $ 282,336 (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market.
Schedule of assets measured at fair value on a nonrecurring basis	The following tables present the Company’s assets that are measured at fair value on a nonrecurring basis. September 30, 2018 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Total Losses Total Losses (Amounts in Thousands) Loans (4) Agricultural $ — $ — $ 1,401 $ 1,401 $ — $ 63 Commercial and financial — — 2,039 2,039 (14 ) 122 Real Estate: — Construction, 1 to 4 family residential — — — — — — Construction, land development and commercial — — 701 701 — — Mortgage, farmland — — 3,964 3,964 — — Mortgage, 1 to 4 family first liens — — 6,232 6,232 169 313 Mortgage, 1 to 4 family junior liens — — 22 22 — 60 Mortgage, multi-family — — 6,180 6,180 — — Mortgage, commercial — — 1,502 1,502 186 258 Loans to individuals — — — — — — Foreclosed assets (5) — — — — — — Total $ — $ — $ 22,041 $ 22,041 $ 341 $ 816 (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. (4) Represents carrying value and related write-downs of loans for which adjustments are based on the value of the collateral. The carrying value of loans fully-charged off is zero . (5) Represents the fair value and related losses of foreclosed real estate and other collateral owned that were measured at fair value subsequent to their initial classification as foreclosed assets. Assets and Liabilities Recorded at Fair Value on a Nonrecurring Basis (continued) December 31, 2017 Year Ended December 31, 2017 Readily Available Market Prices(1) Observable Market Prices(2) Company Determined Market Prices(3) Total at Fair Value Total Losses (Amounts in Thousands) Loans (4) Agricultural $ — $ — $ 4,704 $ 4,704 $ 127 Commercial and financial — — 1,555 1,555 159 Real Estate: Construction, 1 to 4 family residential — — 729 729 — Construction, land development and commercial — — — — — Mortgage, farmland — — 7,190 7,190 — Mortgage, 1 to 4 family first liens — — 5,548 5,548 404 Mortgage, 1 to 4 family junior liens — — 25 25 88 Mortgage, multi-family — — 6,397 6,397 — Mortgage, commercial — — 1,063 1,063 111 Loans to individuals — — — — 20 Foreclosed assets (5) — — — — — Total $ — $ — $ 27,211 $ 27,211 $ 909 (1) Considered Level 1 under ASC 820. (2) Considered Level 2 under ASC 820. (3) Considered Level 3 under ASC 820 and are based on valuation models that use significant assumptions that are not observable in an active market. (4) Represents carrying value and related write-downs of loans for which adjustments are based on the value of the collateral. The carrying value of loans fully-charged off is zero. (5) Represents the fair value and related losses of foreclosed real estate and other collateral owned that were measured at fair value subsequent to their initial classification as foreclosed assets.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of banks commitments	A summary of the Bank’s commitments at September 30, 2018 and December 31, 2017 is as follows: September 30, 2018 December 31, 2017 (Amounts In Thousands) Firm loan commitments and unused portion of lines of credit: Home equity loans $ 60,442 $ 55,171 Credit cards 52,882 49,235 Commercial, real estate and home construction 104,426 117,021 Commercial lines and real estate purchase loans 189,351 159,450 Outstanding letters of credit 7,841 9,113

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Identification of the balance sheet category and fair values of the derivative instruments designated as cash flow hedges	The table below identifies the balance sheet category and fair values of the Bank’s derivative instruments designated as cash flow hedges as of September 30, 2018 and December 31, 2017 : Notional Amount Fair Value Balance Sheet Category Maturity (Amounts in Thousands) September 30, 2018 Interest rate swap $ 25,000 $ 26 Other Liabilities 11/9/2020 Interest rate swap 25,000 (958 ) Other Liabilities 11/7/2023 December 31, 2017 Interest rate swap $ 25,000 $ (582 ) Other Liabilities 11/9/2020 Interest rate swap 25,000 (2,237 ) Other Liabilities 11/7/2023
Identification of the gains and losses recognized on the derivative instruments designated as cash flow hedges	The table below identifies the gains and losses recognized on the Bank’s derivative instruments designated as cash flow hedges for the nine months ended September 30, 2018 and year ended December 31, 2017 : Effective Portion Ineffective Portion Recognized in OCI Reclassifed from AOCI into Income Recognized in Income on Derivatives Amount of Gain (Loss) Category Amount of Gain (Loss) Category Amount of Gain (Loss) (Amounts in Thousands) September 30, 2018 Interest rate swap $ 457 Interest Expense $ — Other Income $ — Interest rate swap 960 Interest Expense — Other Income — December 31, 2017 Interest rate swap $ 318 Interest Expense $ — Other Income $ — Interest rate swap 373 Interest Expense — Other Income —

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018segment	Jan. 01, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Document Fiscal Year Focus	2,018
Number of operating segments | segment	1
Scenario, Forecast [Member] | Accounting Standards Update 2016-02 [Member] | Minimum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, liability		$ 3
Operating lease, right-of-use asset		3
Scenario, Forecast [Member] | Accounting Standards Update 2016-02 [Member] | Maximum [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, liability		3.5
Operating lease, right-of-use asset		$ 3.5

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Summary of computation of basic and diluted earnings per share [Abstract]
Common shares outstanding at the beginning of the period (shares)					9,373,666	9,335,154	9,329,514	9,264,227
Weighted average number of net shares issued (redeemed) (shares)	(22,223)	(4,596)	40,123	64,144
Weighted average shares outstanding (basic) (shares)	9,351,443	9,324,918	9,375,277	9,328,371
Weighted average of potential dilutive shares attributable to stock options granted, computed under the treasury stock method (shares)	4,245	3,559	4,067	4,874
Weighted average number of shares (diluted) (shares)	9,355,688	9,328,477	9,379,344	9,333,245
Net income (In thousands)	$ 10,050	$ 8,552	$ 30,971	$ 23,883
Earnings per share:
Basic (in dollars per share)	$ 1.07	$ 0.92	$ 3.30	$ 2.56
Diluted (in dollars per share)	$ 1.07	$ 0.92	$ 3.30	$ 2.56

Other Comprehensive Income (L_3

Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Tax effect	$ 1,478	$ 1,514
Net-of-tax amount	(4,444)	(2,446)
Net unrealized loss on available-for-sale securities [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Net unrealized gain (loss)	(4,990)	(1,141)
Net unrealized loss on derivatives used for cash flow hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Net unrealized gain (loss)	$ (932)	$ (2,819)

Securities (Details)

Securities (Details) $ in Thousands	Sep. 30, 2018USD ($)security	Dec. 31, 2017USD ($)security
Securities available for sale
Securities available for sale, Percent	100.00%	100.00%
Available-for-sale Securities Reconciliation [Abstract]
Amortized Cost	$ 297,292	$ 286,296
Gross Unrealized Gains	130	723
Gross Unrealized (Losses)	(5,120)	(1,864)
Amortized Cost
Due in one year or less	41,457
Due after one year through five years	180,463
Due after five years through ten years	74,811
Due over ten years	561
Fair Value
Due in one year or less	41,340
Due after one year through five years	177,642
Due after five years through ten years	72,759
Due over ten years	561
Carrying value of investment securities pledged to collateralize short-term borrowings	$ 292,302	$ 285,155
Less than 12 months
Number of securities | security	402	272
Fair Value	$ 155,155	$ 134,532
Unrealized Loss	$ (2,486)	$ (1,034)
Percentage	1.60%	0.77%
12 months or more
Number of securities | security	165	74
Fair Value	$ 90,239	$ 37,491
Unrealized Loss	$ (2,634)	$ (830)
Percentage	2.92%	2.21%
Total
Number of securities | security	567	346
Fair Value	$ 245,394	$ 172,023
Unrealized Loss	$ (5,120)	$ (1,864)
Percentage	2.09%	1.08%
Collateralized Securities [Member]
Fair Value
Carrying value of investment securities pledged to collateralize short-term borrowings	$ 12,190
U.S. Treasury [Member]
Securities available for sale
Securities available for sale, Percent	28.18%	19.05%
Available-for-sale Securities Reconciliation [Abstract]
Amortized Cost	$ 83,949	$ 54,696
Gross Unrealized Gains	0	0
Gross Unrealized (Losses)	(1,596)	(378)
Fair Value
Carrying value of investment securities pledged to collateralize short-term borrowings	$ 82,353	$ 54,318
Less than 12 months
Number of securities | security	24	22
Fair Value	$ 58,023	$ 54,318
Unrealized Loss	$ (987)	$ (378)
Percentage	1.70%	0.70%
12 months or more
Number of securities | security	10	0
Fair Value	$ 24,330	$ 0
Unrealized Loss	$ (609)	$ 0
Percentage	2.50%	0.00%
Total
Number of securities | security	34	22
Fair Value	$ 82,353	$ 54,318
Unrealized Loss	$ (1,596)	$ (378)
Percentage	1.94%	0.70%
Other securities [Member]
Securities available for sale
Securities available for sale, Percent	11.88%	15.42%
Available-for-sale Securities Reconciliation [Abstract]
Amortized Cost	$ 35,398	$ 44,470
Gross Unrealized Gains	1	1
Gross Unrealized (Losses)	(666)	(512)
Fair Value
Carrying value of investment securities pledged to collateralize short-term borrowings	$ 34,733	$ 43,959
Less than 12 months
Number of securities | security	1	9
Fair Value	$ 2,494	$ 21,411
Unrealized Loss	$ (9)	$ (83)
Percentage	0.36%	0.39%
12 months or more
Number of securities | security	13	9
Fair Value	$ 32,239	$ 22,547
Unrealized Loss	$ (657)	$ (429)
Percentage	2.04%	1.90%
Total
Number of securities | security	14	18
Fair Value	$ 34,733	$ 43,958
Unrealized Loss	$ (666)	$ (512)
Percentage	1.92%	1.16%
State and political subdivisions [Member]
Securities available for sale
Securities available for sale, Percent	59.94%	65.53%
Available-for-sale Securities Reconciliation [Abstract]
Amortized Cost	$ 177,945	$ 187,130
Gross Unrealized Gains	129	722
Gross Unrealized (Losses)	(2,858)	(974)
Fair Value
Carrying value of investment securities pledged to collateralize short-term borrowings	$ 175,216	$ 186,878
Less than 12 months
Number of securities | security	377	241
Fair Value	$ 94,638	$ 58,803
Unrealized Loss	$ (1,490)	$ (573)
Percentage	1.57%	0.97%
12 months or more
Number of securities | security	142	65
Fair Value	$ 33,670	$ 14,944
Unrealized Loss	$ (1,368)	$ (401)
Percentage	4.06%	2.68%
Total
Number of securities | security	519	306
Fair Value	$ 128,308	$ 73,747
Unrealized Loss	$ (2,858)	$ (974)
Percentage	2.23%	1.32%

Loans (Details)

Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Summary of classes of loans (abstract)
Loans and receivable	$ 2,555,782	$ 2,459,671	$ 2,419,894
Net unamortized fees and costs	948	894
Loans and receivable, gross	2,556,730	2,460,565
Less allowance for loan losses	31,010	29,400
Loans and receivable, net	2,525,720	2,431,165
Agricultural [Member]
Summary of classes of loans (abstract)
Loans and receivable	79,155	88,580	76,484
Commercial and financial [Member]
Summary of classes of loans (abstract)
Loans and receivable	214,681	218,632	214,199
Real Estate: Construction, 1 to 4 family residential [Member]
Summary of classes of loans (abstract)
Loans and receivable	65,932	69,738
Real Estate: Construction, land development and commercial [Member]
Summary of classes of loans (abstract)
Loans and receivable	106,012	109,595
Real Estate: Mortgage, farmland [Member]
Summary of classes of loans (abstract)
Loans and receivable	230,032	215,286	$ 208,982
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Summary of classes of loans (abstract)
Loans and receivable	899,937	831,591
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Summary of classes of loans (abstract)
Loans and receivable	149,312	144,200
Real Estate: Mortgage, multi-family [Member]
Summary of classes of loans (abstract)
Loans and receivable	347,660	336,810
Real Estate: Mortgage, commercial [Member]
Summary of classes of loans (abstract)
Loans and receivable	381,966	361,196
Loans to individuals [Member]
Summary of classes of loans (abstract)
Loans and receivable	27,946	26,417
Obligations of state and political subdivisions [Member]
Summary of classes of loans (abstract)
Loans and receivable	$ 53,149	$ 57,626

Loans, Allowance For Credit Los

Loans, Allowance For Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 29,510	$ 28,950	$ 29,400	$ 26,530
Charge-offs	(893)	(305)	(1,707)	(1,464)
Recoveries	800	575	1,778	2,457
Provision	1,593	130	1,539	1,827
Ending balance	31,010	29,350	31,010	29,350
Ending balance, individually evaluated for impairment	1,465	3,000	1,465	3,000
Ending balance, collectively evaluated for impairment	29,545	26,350	29,545	26,350
Loan [Abstract]
Total Loans Receivable	2,555,782	2,419,894	2,555,782	2,419,894	$ 2,459,671
Ending balance, individually evaluated for impairment	25,279	33,785	25,279	33,785
Ending balance, collectively evaluated for impairment	2,530,503	2,386,109	2,530,503	2,386,109
Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	2,071	2,341	2,294	2,947
Charge-offs	(68)	(27)	(72)	(66)
Recoveries	74	56	102	123
Provision	(47)	92	(294)	(542)
Ending balance	2,030	2,462	2,030	2,462
Ending balance, individually evaluated for impairment	118	653	118	653
Ending balance, collectively evaluated for impairment	1,912	1,809	1,912	1,809
Loan [Abstract]
Total Loans Receivable	79,155	76,484	79,155	76,484	88,580
Ending balance, individually evaluated for impairment	2,342	6,181	2,342	6,181
Ending balance, collectively evaluated for impairment	76,813	70,303	76,813	70,303
Commercial and Financial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	5,040	4,586	4,837	4,531
Charge-offs	(241)	(21)	(447)	(478)
Recoveries	415	219	856	882
Provision	(133)	(43)	(165)	(194)
Ending balance	5,081	4,741	5,081	4,741
Ending balance, individually evaluated for impairment	1,165	913	1,165	913
Ending balance, collectively evaluated for impairment	3,916	3,828	3,916	3,828
Loan [Abstract]
Total Loans Receivable	214,681	214,199	214,681	214,199	218,632
Ending balance, individually evaluated for impairment	3,288	2,985	3,288	2,985
Ending balance, collectively evaluated for impairment	211,393	211,214	211,393	211,214
Real Estate: Construction and land development [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,054	3,165	2,989	2,890
Charge-offs	0	0	0	(114)
Recoveries	2	33	147	443
Provision	(188)	(182)	(268)	(203)
Ending balance	2,868	3,016	2,868	3,016
Ending balance, individually evaluated for impairment	3	46	3	46
Ending balance, collectively evaluated for impairment	2,865	2,970	2,865	2,970
Loan [Abstract]
Total Loans Receivable	171,944	180,574	171,944	180,574
Ending balance, individually evaluated for impairment	927	1,161	927	1,161
Ending balance, collectively evaluated for impairment	171,017	179,413	171,017	179,413
Real Estate: Mortgage, farmland [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,475	4,009	3,669	3,417
Charge-offs	0	(3)	0	(3)
Recoveries	10	0	29	0
Provision	50	2	(163)	594
Ending balance	3,535	4,008	3,535	4,008
Ending balance, individually evaluated for impairment	0	784	0	784
Ending balance, collectively evaluated for impairment	3,535	3,224	3,535	3,224
Loan [Abstract]
Total Loans Receivable	230,032	208,982	230,032	208,982	$ 215,286
Ending balance, individually evaluated for impairment	3,729	8,179	3,729	8,179
Ending balance, collectively evaluated for impairment	226,303	200,803	226,303	200,803
Real Estate: Mortgage, 1 to 4 family [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	8,902	8,340	8,668	7,677
Charge-offs	(280)	(55)	(607)	(263)
Recoveries	187	203	433	570
Provision	1,756	98	2,071	602
Ending balance	10,565	8,586	10,565	8,586
Ending balance, individually evaluated for impairment	91	110	91	110
Ending balance, collectively evaluated for impairment	10,474	8,476	10,474	8,476
Loan [Abstract]
Total Loans Receivable	1,049,249	960,800	1,049,249	960,800
Ending balance, individually evaluated for impairment	6,728	7,097	6,728	7,097
Ending balance, collectively evaluated for impairment	1,042,521	953,703	1,042,521	953,703
Real Estate: Mortgage, multi-family and commercial [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	5,697	5,414	5,700	4,045
Charge-offs	(107)	(86)	(161)	(130)
Recoveries	80	7	97	236
Provision	193	107	227	1,291
Ending balance	5,863	5,442	5,863	5,442
Ending balance, individually evaluated for impairment	40	409	40	409
Ending balance, collectively evaluated for impairment	5,823	5,033	5,823	5,033
Loan [Abstract]
Total Loans Receivable	729,626	694,771	729,626	694,771
Ending balance, individually evaluated for impairment	8,217	8,097	8,217	8,097
Ending balance, collectively evaluated for impairment	721,409	686,674	721,409	686,674
Others [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	1,271	1,095	1,243	1,023
Charge-offs	(197)	(113)	(420)	(410)
Recoveries	32	57	114	203
Provision	(38)	56	131	279
Ending balance	1,068	1,095	1,068	1,095
Ending balance, individually evaluated for impairment	48	85	48	85
Ending balance, collectively evaluated for impairment	1,020	1,010	1,020	1,010
Loan [Abstract]
Total Loans Receivable	81,095	84,084	81,095	84,084
Ending balance, individually evaluated for impairment	48	85	48	85
Ending balance, collectively evaluated for impairment	$ 81,047	$ 83,999	$ 81,047	$ 83,999

Loans, Credit Quality Indicator

Loans, Credit Quality Indicators (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	$ 2,555,782	$ 2,459,671	$ 2,419,894
Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	77,567	78,743
Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	362,588	393,338
Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,658,356	1,586,032
Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	353,802	305,842
Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	49,477	43,374
Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	53,992	52,342
Agricultural [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	79,155	88,580	76,484
Agricultural [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	2,466	2,585
Agricultural [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	13,521	15,755
Agricultural [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	37,824	40,886
Agricultural [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	19,630	17,009
Agricultural [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	901	6,898
Agricultural [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	4,813	5,447
Commercial and Financial [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	214,681	218,632	214,199
Commercial and Financial [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	2,858	10,264
Commercial and Financial [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	46,227	51,620
Commercial and Financial [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	118,659	116,375
Commercial and Financial [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	33,612	29,392
Commercial and Financial [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	7,095	5,576
Commercial and Financial [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	6,230	5,405
Real Estate: Construction, 1 to 4 family residential [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	65,932	69,738
Real Estate: Construction, 1 to 4 family residential [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	0	0
Real Estate: Construction, 1 to 4 family residential [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	11,782	4,710
Real Estate: Construction, 1 to 4 family residential [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	39,457	47,995
Real Estate: Construction, 1 to 4 family residential [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	13,516	15,188
Real Estate: Construction, 1 to 4 family residential [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	782	1,845
Real Estate: Construction, 1 to 4 family residential [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	395	0
Real Estate: Construction, land development and commercial [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	106,012	109,595
Real Estate: Construction, land development and commercial [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	393	2,548
Real Estate: Construction, land development and commercial [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	22,648	27,296
Real Estate: Construction, land development and commercial [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	57,043	35,749
Real Estate: Construction, land development and commercial [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	24,687	39,760
Real Estate: Construction, land development and commercial [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	178	3,358
Real Estate: Construction, land development and commercial [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,063	884
Real Estate: Mortgage, farmland [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	230,032	215,286	$ 208,982
Real Estate: Mortgage, farmland [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	3,700	4,751
Real Estate: Mortgage, farmland [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	52,301	54,409
Real Estate: Mortgage, farmland [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	123,898	109,724
Real Estate: Mortgage, farmland [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	36,890	32,655
Real Estate: Mortgage, farmland [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	3,983	5,306
Real Estate: Mortgage, farmland [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	9,260	8,441
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	899,937	831,591
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	2,360	2,392
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	33,045	30,094
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	741,877	689,645
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	91,612	76,766
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	11,031	12,072
Real Estate: Mortgage, 1 to 4 family first liens [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	20,012	20,622
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	149,312	144,200
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	524	489
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	3,931	4,527
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	136,420	130,451
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	4,930	4,881
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,549	1,834
Real Estate: Mortgage, 1 to 4 family junior liens [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	1,958	2,018
Real Estate: Mortgage, multi-family [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	347,660	336,810
Real Estate: Mortgage, multi-family [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	22,139	16,564
Real Estate: Mortgage, multi-family [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	70,444	75,768
Real Estate: Mortgage, multi-family [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	176,519	195,652
Real Estate: Mortgage, multi-family [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	59,380	42,373
Real Estate: Mortgage, multi-family [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	12,910	0
Real Estate: Mortgage, multi-family [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	6,268	6,453
Real Estate: Mortgage, commercial [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	381,966	361,196
Real Estate: Mortgage, commercial [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	34,798	30,355
Real Estate: Mortgage, commercial [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	92,947	98,434
Real Estate: Mortgage, commercial [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	181,337	179,417
Real Estate: Mortgage, commercial [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	58,165	43,786
Real Estate: Mortgage, commercial [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	10,842	6,303
Real Estate: Mortgage, commercial [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	3,877	2,901
Loans to individuals [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	27,946	26,417
Loans to individuals [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	0	1
Loans to individuals [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	119	118
Loans to individuals [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	26,800	25,445
Loans to individuals [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	705	500
Loans to individuals [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	206	182
Loans to individuals [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	116	171
Obligations of state and political subdivisions [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	53,149	57,626
Obligations of state and political subdivisions [Member] | Excellent [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	8,329	8,794
Obligations of state and political subdivisions [Member] | Good [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	15,623	30,607
Obligations of state and political subdivisions [Member] | Satisfactory [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	18,522	14,693
Obligations of state and political subdivisions [Member] | Monitor [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	10,675	3,532
Obligations of state and political subdivisions [Member] | Special Mention [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	0	0
Obligations of state and political subdivisions [Member] | Substandard [Member]
Summary of credit quality indicators by type of loans [Abstract]
Loans and receivable	$ 0	$ 0

Loans, Past Due Receivables (De

Loans, Past Due Receivables (Details) $ in Thousands	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of accruing loans past due 90 days or more	3	8
Schedule of past due loans [Abstract]
Total Past Due	$ 11,299	$ 12,963
Current	2,544,483	2,446,708
Total Loans Receivable	2,555,782	2,459,671	$ 2,419,894
Accruing Loans Past Due 90 Days or More	338	971
Agricultural [Member]
Schedule of past due loans [Abstract]
Total Past Due	716	593
Current	78,439	87,987
Total Loans Receivable	79,155	88,580	76,484
Accruing Loans Past Due 90 Days or More	0	0
Commercial and Financial [Member]
Schedule of past due loans [Abstract]
Total Past Due	1,536	560
Current	213,145	218,072
Total Loans Receivable	214,681	218,632	214,199
Accruing Loans Past Due 90 Days or More	0	0
Real Estate: Construction, 1 to 4 family residential [Member]
Schedule of past due loans [Abstract]
Total Past Due	1,003	0
Current	64,929	69,738
Total Loans Receivable	65,932	69,738
Accruing Loans Past Due 90 Days or More	0	0
Real Estate: Construction, land development and commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	458	246
Current	105,554	109,349
Total Loans Receivable	106,012	109,595
Accruing Loans Past Due 90 Days or More	0	0
Real Estate: Mortgage, farmland [Member]
Schedule of past due loans [Abstract]
Total Past Due	991	269
Current	229,041	215,017
Total Loans Receivable	230,032	215,286	$ 208,982
Accruing Loans Past Due 90 Days or More	0	0
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	5,609	9,832
Current	894,328	821,759
Total Loans Receivable	899,937	831,591
Accruing Loans Past Due 90 Days or More	338	971
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	147	695
Current	149,165	143,505
Total Loans Receivable	149,312	144,200
Accruing Loans Past Due 90 Days or More	0	0
Real Estate: Mortgage, multi-family [Member]
Schedule of past due loans [Abstract]
Total Past Due	152	0
Current	347,508	336,810
Total Loans Receivable	347,660	336,810
Accruing Loans Past Due 90 Days or More	0	0
Real Estate: Mortgage, commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	484	501
Current	381,482	360,695
Total Loans Receivable	381,966	361,196
Accruing Loans Past Due 90 Days or More	0	0
Loans to individuals [Member]
Schedule of past due loans [Abstract]
Total Past Due	203	267
Current	27,743	26,150
Total Loans Receivable	27,946	26,417
Accruing Loans Past Due 90 Days or More	0	0
State and political subdivisions [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
Current	53,149	57,626
Total Loans Receivable	53,149	57,626
Accruing Loans Past Due 90 Days or More	0	0
30 - 59 Days Past Due [Member]
Schedule of past due loans [Abstract]
Total Past Due	3,852	7,521
30 - 59 Days Past Due [Member] | Agricultural [Member]
Schedule of past due loans [Abstract]
Total Past Due	474	324
30 - 59 Days Past Due [Member] | Commercial and Financial [Member]
Schedule of past due loans [Abstract]
Total Past Due	991	447
30 - 59 Days Past Due [Member] | Real Estate: Construction, 1 to 4 family residential [Member]
Schedule of past due loans [Abstract]
Total Past Due	566	0
30 - 59 Days Past Due [Member] | Real Estate: Construction, land development and commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	458	246
30 - 59 Days Past Due [Member] | Real Estate: Mortgage, farmland [Member]
Schedule of past due loans [Abstract]
Total Past Due	240	269
30 - 59 Days Past Due [Member] | Real Estate: Mortgage, 1 to 4 family first liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	780	5,143
30 - 59 Days Past Due [Member] | Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	59	579
30 - 59 Days Past Due [Member] | Real Estate: Mortgage, multi-family [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
30 - 59 Days Past Due [Member] | Real Estate: Mortgage, commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	135	307
30 - 59 Days Past Due [Member] | Loans to individuals [Member]
Schedule of past due loans [Abstract]
Total Past Due	149	206
30 - 59 Days Past Due [Member] | State and political subdivisions [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
60 - 89 Days Past Due [Member]
Schedule of past due loans [Abstract]
Total Past Due	4,684	2,119
60 - 89 Days Past Due [Member] | Agricultural [Member]
Schedule of past due loans [Abstract]
Total Past Due	84	0
60 - 89 Days Past Due [Member] | Commercial and Financial [Member]
Schedule of past due loans [Abstract]
Total Past Due	545	20
60 - 89 Days Past Due [Member] | Real Estate: Construction, 1 to 4 family residential [Member]
Schedule of past due loans [Abstract]
Total Past Due	437	0
60 - 89 Days Past Due [Member] | Real Estate: Construction, land development and commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
60 - 89 Days Past Due [Member] | Real Estate: Mortgage, farmland [Member]
Schedule of past due loans [Abstract]
Total Past Due	751	0
60 - 89 Days Past Due [Member] | Real Estate: Mortgage, 1 to 4 family first liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	2,225	1,750
60 - 89 Days Past Due [Member] | Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	88	116
60 - 89 Days Past Due [Member] | Real Estate: Mortgage, multi-family [Member]
Schedule of past due loans [Abstract]
Total Past Due	152	0
60 - 89 Days Past Due [Member] | Real Estate: Mortgage, commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	349	178
60 - 89 Days Past Due [Member] | Loans to individuals [Member]
Schedule of past due loans [Abstract]
Total Past Due	53	55
60 - 89 Days Past Due [Member] | State and political subdivisions [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
90 Days or More Past Due [Member]
Schedule of past due loans [Abstract]
Total Past Due	2,763	3,323
90 Days or More Past Due [Member] | Agricultural [Member]
Schedule of past due loans [Abstract]
Total Past Due	158	269
90 Days or More Past Due [Member] | Commercial and Financial [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	93
90 Days or More Past Due [Member] | Real Estate: Construction, 1 to 4 family residential [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
90 Days or More Past Due [Member] | Real Estate: Construction, land development and commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
90 Days or More Past Due [Member] | Real Estate: Mortgage, farmland [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
90 Days or More Past Due [Member] | Real Estate: Mortgage, 1 to 4 family first liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	2,604	2,939
90 Days or More Past Due [Member] | Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
90 Days or More Past Due [Member] | Real Estate: Mortgage, multi-family [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	0
90 Days or More Past Due [Member] | Real Estate: Mortgage, commercial [Member]
Schedule of past due loans [Abstract]
Total Past Due	0	16
90 Days or More Past Due [Member] | Loans to individuals [Member]
Schedule of past due loans [Abstract]
Total Past Due	1	6
90 Days or More Past Due [Member] | State and political subdivisions [Member]
Schedule of past due loans [Abstract]
Total Past Due	$ 0	$ 0

Loans, Impaired Financing Recei

Loans, Impaired Financing Receivable Loan Type (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)	Dec. 31, 2017USD ($)
Summary of certain impaired loan information [Abstract]
Non-accrual loans	$ 9,322	$ 9,096
Accruing loans past due 90 days or more	338	971
TDR loans	7,835	$ 8,470
Decrease accruing loans past due 90 days or more	$ 630
Number of accruing loans past due 90 days or more	3	8
Average 90 days or more past due loan balance	$ 110	$ 120
Agricultural [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	1,401	1,651
Accruing loans past due 90 days or more	0	0
TDR loans	72	2,309
Commercial and financial [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	489	825
Accruing loans past due 90 days or more	0	0
TDR loans	1,845	1,943
Real Estate: Construction, 1 to 4 family residential [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	0	0
Accruing loans past due 90 days or more	0	0
TDR loans	0	0
Real Estate: Construction, land development and commercial [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	0	0
Accruing loans past due 90 days or more	0	0
TDR loans	330	339
Real Estate: Mortgage, farmland [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	1,167	1,391
Accruing loans past due 90 days or more	0	0
TDR loans	3,313	1,451
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	5,064	4,407
Accruing loans past due 90 days or more	338	971
TDR loans	1,302	1,357
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	0	7
Accruing loans past due 90 days or more	0	0
TDR loans	25	25
Real Estate: Mortgage, multi-family [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	152	218
Accruing loans past due 90 days or more	0	0
TDR loans	0	0
Real Estate: Mortgage, commercial [Member]
Summary of certain impaired loan information [Abstract]
Non-accrual loans	1,049	597
Accruing loans past due 90 days or more	0	0
TDR loans	948	1,046
Loans to individuals [Member]
Summary of certain impaired loan information [Abstract]
Accruing loans past due 90 days or more	0	0
Troubled Debt Restructuring [Member]
Summary of certain impaired loan information [Abstract]
TDR Loans included within nonaccrual loans	$ 4,150	$ 3,620

Loans, Troubled Debt Restructur

Loans, Troubled Debt Restructuring (Details) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)contract	Sep. 30, 2018USD ($)contractloan	Dec. 31, 2017USD ($)contractloan
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	$ 667	$ 667	$ 530
Summary of information for TDR loans [Abstract]
Number of contracts | contract		54	54
Recorded investment	$ 11,982	$ 11,982	$ 12,094
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	3	14
Pre-modification recorded investment	$ 658	$ 6,964
Post-modification recorded investment	658	6,964
Commitments to lend additional borrowings			$ 530
TDR loans default payment		$ 0
Number of TDR loans default payment | loan		0	0
Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	582	$ 582	$ 321
Summary of information for TDR loans [Abstract]
Number of contracts | contract		4	9
Recorded investment	$ 1,306	$ 1,306	$ 3,628
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Commercial and Financial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	85	$ 85	$ 169
Summary of information for TDR loans [Abstract]
Number of contracts | contract		13	14
Recorded investment	$ 2,269	$ 2,269	$ 2,575
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	2	4
Pre-modification recorded investment	$ 80	$ 541
Post-modification recorded investment	80	541
Real Estate: Construction, 1 to 4 family residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 16
Summary of information for TDR loans [Abstract]
Number of contracts | contract		0	0
Recorded investment	$ 0	$ 0	$ 0
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Construction, land development and commercial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		2	2
Recorded investment	$ 330	$ 330	$ 339
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Mortgage, farmland [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		8	7
Recorded investment	$ 4,407	$ 4,407	$ 2,761
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	2
Pre-modification recorded investment	$ 0	$ 4,944
Post-modification recorded investment	0	4,944
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		17	13
Recorded investment	$ 1,760	$ 1,760	$ 1,442
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	6
Pre-modification recorded investment	$ 0	$ 627
Post-modification recorded investment	0	627
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 24
Summary of information for TDR loans [Abstract]
Number of contracts | contract		1	1
Recorded investment	$ 25	$ 25	$ 25
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Mortgage, multi-family [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		0	0
Recorded investment	$ 0	$ 0	$ 0
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	0	0
Pre-modification recorded investment	$ 0	$ 0
Post-modification recorded investment	0	0
Real Estate: Mortgage, commercial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		9	8
Recorded investment	$ 1,885	$ 1,885	$ 1,324
Summary of troubled debt restructuring loans were modified [Abstract]
Number of contracts | contract	1	2
Pre-modification recorded investment	$ 578	$ 852
Post-modification recorded investment	578	852
Loans to individuals [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable Troubled Debt Restructuring Commitments Outstanding	0	$ 0	$ 0
Summary of information for TDR loans [Abstract]
Number of contracts | contract		0	0
Recorded investment	$ 0	$ 0	$ 0

Loans, Impaired Financing Rec_2

Loans, Impaired Financing Receivables Activity (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Recorded Investment
With no related allowance recorded	$ 15,545	$ 15,545	$ 14,356
With an allowance recorded	9,734	9,734	17,131
Total impaired loans	25,279	25,279	31,487
Unpaid Principal Balance
With no related allowance recorded	19,535	19,535	18,735
With an allowance recorded	9,890	9,890	17,202
Total	29,425	29,425	35,937
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	1,465	1,465	2,166
Total	1,465	1,465	$ 2,166
Average Recorded Investment
With no related allowance recorded	16,571	15,207
With an allowance recorded	9,816	10,167
Total	26,387	25,374
Interest Income Recognized
With no related allowance recorded	85	200
With an allowance recorded	112	346
Total	$ 197	546
Decrease in impaired loans		$ 6,210
Percentages of impaired loans to loans held for investment (in hundredths)	0.99%	0.99%	1.28%
Decrease accruing loans past days or more financing receivable unpaid principal balance		$ 630
Decrease in TDR loans		110
Increase in impaired loans with no specific allowance for losses		1,190
Increase in nonaccrual loans		$ 230
Prior period within which impairment is being measured		1 year
Number of period within which average appraisals obtained		1 month
Agricultural and Farmland Real Estate [Member]
Interest Income Recognized
Decrease in impaired loans		$ 7,400
Agricultural [Member]
Recorded Investment
With no related allowance recorded	$ 2,224	2,224	$ 1,822
With an allowance recorded	118	118	3,094
Total impaired loans	2,342	2,342	4,916
Unpaid Principal Balance
With no related allowance recorded	2,525	2,525	2,193
With an allowance recorded	118	118	3,149
Total	2,643	2,643	5,342
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	118	118	133
Total	118	118	133
Average Recorded Investment
With no related allowance recorded	2,850	1,905
With an allowance recorded	118	184
Total	2,968	2,089
Interest Income Recognized
With no related allowance recorded	15	14
With an allowance recorded	2	8
Total	17	22
Commercial and Financial [Member]
Recorded Investment
With no related allowance recorded	1,515	1,515	1,725
With an allowance recorded	1,773	1,773	1,043
Total impaired loans	3,288	3,288	2,768
Unpaid Principal Balance
With no related allowance recorded	2,208	2,208	2,487
With an allowance recorded	1,873	1,873	1,043
Total	4,081	4,081	3,530
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	1,165	1,165	1,018
Total	1,165	1,165	1,018
Average Recorded Investment
With no related allowance recorded	1,633	1,781
With an allowance recorded	1,821	2,028
Total	3,454	3,809
Interest Income Recognized
With no related allowance recorded	14	44
With an allowance recorded	22	74
Total	36	118
Real Estate: Construction, 1 to 4 family residential [Member]
Recorded Investment
With no related allowance recorded	111	111	114
With an allowance recorded	0	0	0
Total impaired loans	111	111	114
Unpaid Principal Balance
With no related allowance recorded	148	148	150
With an allowance recorded	0	0	0
Total	148	148	150
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	0	0	0
Total	0	0	0
Average Recorded Investment
With no related allowance recorded	111	113
With an allowance recorded	0	0
Total	111	113
Interest Income Recognized
With no related allowance recorded	1	4
With an allowance recorded	0	0
Total	1	4
Real Estate: Construction, land development and commercial [Member]
Recorded Investment
With no related allowance recorded	330	330	338
With an allowance recorded	486	486	505
Total impaired loans	816	816	843
Unpaid Principal Balance
With no related allowance recorded	347	347	371
With an allowance recorded	486	486	505
Total	833	833	876
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	3	3	39
Total	3	3	39
Average Recorded Investment
With no related allowance recorded	331	334
With an allowance recorded	492	495
Total	823	829
Interest Income Recognized
With no related allowance recorded	3	10
With an allowance recorded	6	17
Total	9	27
Real Estate: Mortgage, farmland [Member]
Recorded Investment
With no related allowance recorded	3,729	3,729	2,523
With an allowance recorded	0	0	5,439
Total impaired loans	3,729	3,729	7,962
Unpaid Principal Balance
With no related allowance recorded	4,147	4,147	2,902
With an allowance recorded	0	0	5,439
Total	4,147	4,147	8,341
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	0	0	238
Total	0	0	238
Average Recorded Investment
With no related allowance recorded	3,744	3,126
With an allowance recorded	0	0
Total	3,744	3,126
Interest Income Recognized
With no related allowance recorded	32	67
With an allowance recorded	0	0
Total	32	67
Real Estate: Mortgage, 1 to 4 family first liens [Member]
Recorded Investment
With no related allowance recorded	5,562	5,562	6,045
With an allowance recorded	1,142	1,142	577
Total impaired loans	6,704	6,704	6,622
Unpaid Principal Balance
With no related allowance recorded	7,162	7,162	7,507
With an allowance recorded	1,198	1,198	593
Total	8,360	8,360	8,100
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	88	88	63
Total	88	88	63
Average Recorded Investment
With no related allowance recorded	5,708	5,827
With an allowance recorded	1,147	1,169
Total	6,855	6,996
Interest Income Recognized
With no related allowance recorded	10	29
With an allowance recorded	10	30
Total	20	59
Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Recorded Investment
With no related allowance recorded	0	0	7
With an allowance recorded	24	24	25
Total impaired loans	24	24	32
Unpaid Principal Balance
With no related allowance recorded	256	256	482
With an allowance recorded	24	24	25
Total	280	280	507
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	3	3	3
Total	3	3	3
Average Recorded Investment
With no related allowance recorded	0	0
With an allowance recorded	25	25
Total	25	25
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	0	1
Total	0	1
Real Estate: Mortgage, multi-family [Member]
Recorded Investment
With no related allowance recorded	152	152	218
With an allowance recorded	6,067	6,067	6,179
Total impaired loans	6,219	6,219	6,397
Unpaid Principal Balance
With no related allowance recorded	218	218	355
With an allowance recorded	6,067	6,067	6,179
Total	6,285	6,285	6,534
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	39	39	480
Total	39	39	480
Average Recorded Investment
With no related allowance recorded	153	156
With an allowance recorded	6,083	6,123
Total	6,236	6,279
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	69	207
Total	69	207
Real Estate: Mortgage, commercial [Member]
Recorded Investment
With no related allowance recorded	1,922	1,922	1,564
With an allowance recorded	76	76	79
Total impaired loans	1,998	1,998	1,643
Unpaid Principal Balance
With no related allowance recorded	2,510	2,510	2,274
With an allowance recorded	76	76	79
Total	2,586	2,586	2,353
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	1	1	2
Total	1	1	2
Average Recorded Investment
With no related allowance recorded	2,041	1,965
With an allowance recorded	76	77
Total	2,117	2,042
Interest Income Recognized
With no related allowance recorded	10	32
With an allowance recorded	1	3
Total	11	35
Loans to individuals [Member]
Recorded Investment
With no related allowance recorded	0	0	0
With an allowance recorded	48	48	190
Total impaired loans	48	48	190
Unpaid Principal Balance
With no related allowance recorded	14	14	14
With an allowance recorded	48	48	190
Total	62	62	204
Related Allowance
With no related allowance recorded	0	0	0
With an allowance recorded	48	48	190
Total	48	48	$ 190
Average Recorded Investment
With no related allowance recorded	0	0
With an allowance recorded	54	66
Total	54	66
Interest Income Recognized
With no related allowance recorded	0	0
With an allowance recorded	2	6
Total	$ 2	$ 6

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Readily Available Market Prices [Member]
Financial instrument assets:
Cash and cash equivalents	$ 192,723	$ 154,353
Investment securities	0	0
Loans held for sale	0	0
Loans
Agricultural	0	0
Commercial and financial	0	0
Real estate:
Construction, 1 to 4 family residential	0	0
Construction, land development and commercial	0	0
Mortgage, farmland	0	0
Mortgage, 1 to 4 family first liens	0	0
Mortgage, 1 to 4 family junior liens	0	0
Mortgage, multi-family	0	0
Mortgage, commercial	0	0
Loans to individuals	0	0
Obligations of state and political subdivisions	0	0
Accrued interest receivable	0	0
Total financial instrument assets	192,723	154,353
Deposits
Noninterest-bearing deposits	0	0
Interest-bearing deposits	0	0
Other borrowings	0	0
Federal Home Loan Bank borrowings	0	0
Interest rate swaps	0
Accrued interest payable	0	0
Total financial instrument liabilities	0	0
Financial instrument with off-balance sheet risk:
Loan commitments	0	0
Letters of credit	0	0
Total financial instrument liabilities with off-balance-sheet risk	0	0
Observable Market Prices [Member]
Financial instrument assets:
Cash and cash equivalents	0	0
Investment securities	304,474	300,160
Loans held for sale	0	5,162
Loans
Agricultural	0	0
Commercial and financial	0	0
Real estate:
Construction, 1 to 4 family residential	0	0
Construction, land development and commercial	0	0
Mortgage, farmland	0	0
Mortgage, 1 to 4 family first liens	0	0
Mortgage, 1 to 4 family junior liens	0	0
Mortgage, multi-family	0	0
Mortgage, commercial	0	0
Loans to individuals	0	0
Obligations of state and political subdivisions	0	0
Accrued interest receivable	12,710	10,772
Total financial instrument assets	317,184	316,094
Deposits
Noninterest-bearing deposits	374,927	363,817
Interest-bearing deposits	2,122,255	1,934,442
Other borrowings	0	0
Federal Home Loan Bank borrowings	207,705	284,442
Interest rate swaps	932	2,819
Accrued interest payable	1,708	1,290
Total financial instrument liabilities	2,707,527	2,586,810
Financial instrument with off-balance sheet risk:
Loan commitments	0	0
Letters of credit	0	0
Total financial instrument liabilities with off-balance-sheet risk	0	0
Company Determined Market Prices [Member]
Financial instrument assets:
Cash and cash equivalents	0	0
Investment securities	0	0
Loans held for sale	3,403	0
Loans
Agricultural	79,007	86,229
Commercial and financial	210,339	212,244
Real estate:
Construction, 1 to 4 family residential	65,949	69,036
Construction, land development and commercial	102,867	108,651
Mortgage, farmland	227,368	211,947
Mortgage, 1 to 4 family first liens	867,383	818,083
Mortgage, 1 to 4 family junior liens	143,265	142,180
Mortgage, multi-family	336,147	329,344
Mortgage, commercial	369,365	353,796
Loans to individuals	27,765	25,610
Obligations of state and political subdivisions	51,762	55,066
Accrued interest receivable	0	0
Total financial instrument assets	2,484,620	2,412,186
Deposits
Noninterest-bearing deposits	0	0
Interest-bearing deposits	0	0
Other borrowings	0	0
Federal Home Loan Bank borrowings	0	0
Interest rate swaps	0
Accrued interest payable	0	0
Total financial instrument liabilities	0	0
Financial instrument with off-balance sheet risk:
Loan commitments	0	0
Letters of credit	0	0
Total financial instrument liabilities with off-balance-sheet risk	0	0
Carrying Amount [Member]
Financial instrument assets:
Cash and cash equivalents	192,723	154,353
Investment securities	304,474	300,160
Loans held for sale	3,403	5,162
Loans
Agricultural	77,125	86,286
Commercial and financial	209,600	213,795
Real estate:
Construction, 1 to 4 family residential	64,755	68,545
Construction, land development and commercial	104,321	107,799
Mortgage, farmland	226,497	211,617
Mortgage, 1 to 4 family first liens	891,649	824,222
Mortgage, 1 to 4 family junior liens	147,983	142,901
Mortgage, multi-family	344,900	334,019
Mortgage, commercial	378,863	358,287
Loans to individuals	27,303	25,635
Obligations of state and political subdivisions	52,724	57,165
Accrued interest receivable	12,710	10,772
Total financial instrument assets	3,039,030	2,900,718
Deposits
Noninterest-bearing deposits	374,927	363,817
Interest-bearing deposits	2,113,825	1,924,748
Other borrowings	0	0
Federal Home Loan Bank borrowings	215,000	295,000
Interest rate swaps	932	2,819
Accrued interest payable	1,708	1,290
Total financial instrument liabilities	2,706,392	2,587,674
Financial instrument with off-balance sheet risk:
Loan commitments	407,101	380,877
Letters of credit	7,841	9,113
Total financial instrument liabilities with off-balance-sheet risk	414,942	389,990
Estimated Fair Value [Member]
Financial instrument assets:
Cash and cash equivalents	192,723	154,353
Investment securities	304,474	300,160
Loans held for sale	3,403	5,162
Loans
Agricultural	79,007	86,229
Commercial and financial	210,339	212,244
Real estate:
Construction, 1 to 4 family residential	65,949	69,036
Construction, land development and commercial	102,867	108,651
Mortgage, farmland	227,368	211,947
Mortgage, 1 to 4 family first liens	867,383	818,083
Mortgage, 1 to 4 family junior liens	143,265	142,180
Mortgage, multi-family	336,147	329,344
Mortgage, commercial	369,365	353,796
Loans to individuals	27,765	25,610
Obligations of state and political subdivisions	51,762	55,066
Accrued interest receivable	12,710	10,772
Total financial instrument assets	2,994,527	2,882,633
Deposits
Noninterest-bearing deposits	374,927	363,817
Interest-bearing deposits	2,122,255	1,934,442
Other borrowings	0	0
Federal Home Loan Bank borrowings	207,705	284,442
Interest rate swaps	932	2,819
Accrued interest payable	1,708	1,290
Total financial instrument liabilities	2,707,527	2,586,810
Financial instrument with off-balance sheet risk:
Loan commitments	0	0
Letters of credit	0	0
Total financial instrument liabilities with off-balance-sheet risk	$ 0	$ 0

Fair Value Measurements, Assets

Fair Value Measurements, Assets and Liabilities Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	$ 292,302	$ 285,155
U.S. Treasury [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	82,353	54,318
State and political subdivisions [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	175,216	186,878
Readily Available Market Prices [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Derivative Financial Instruments	0
Total	192,723	154,353
Observable Market Prices [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Derivative Financial Instruments	(932)	(2,819)
Total	317,184	316,094
Company Determined Market Prices [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Derivative Financial Instruments	0
Total	2,484,620	2,412,186
Recurring Basis [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Total	291,370	282,336
Recurring Basis [Member] | U.S. Treasury [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	82,353	54,318
Recurring Basis [Member] | State and political subdivisions [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	175,216	186,878
Recurring Basis [Member] | Other securities (FHLB, FHLMC and FNMA) [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	34,733	43,959
Recurring Basis [Member] | Interest rate swaps [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Derivative Financial Instruments	(932)	(2,819)
Recurring Basis [Member] | Readily Available Market Prices [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Total	0	0
Recurring Basis [Member] | Readily Available Market Prices [Member] | U.S. Treasury [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	0	0
Recurring Basis [Member] | Readily Available Market Prices [Member] | State and political subdivisions [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	0	0
Recurring Basis [Member] | Readily Available Market Prices [Member] | Other securities (FHLB, FHLMC and FNMA) [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	0	0
Recurring Basis [Member] | Observable Market Prices [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Total	291,370	282,336
Recurring Basis [Member] | Observable Market Prices [Member] | U.S. Treasury [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	82,353	54,318
Recurring Basis [Member] | Observable Market Prices [Member] | State and political subdivisions [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	175,216	186,878
Recurring Basis [Member] | Observable Market Prices [Member] | Other securities (FHLB, FHLMC and FNMA) [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	34,733	43,959
Recurring Basis [Member] | Observable Market Prices [Member] | Interest rate swaps [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Derivative Financial Instruments	(932)	(2,819)
Recurring Basis [Member] | Company Determined Market Prices [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Total	0	0
Recurring Basis [Member] | Company Determined Market Prices [Member] | U.S. Treasury [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	0	0
Recurring Basis [Member] | Company Determined Market Prices [Member] | State and political subdivisions [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	0	0
Recurring Basis [Member] | Company Determined Market Prices [Member] | Other securities (FHLB, FHLMC and FNMA) [Member]
Summary of assets and liabilities measured at fair value on a recurring basis [Abstract]
Securities available for sale	$ 0	$ 0

Fair Value Measurements, Asse_2

Fair Value Measurements, Assets and Liabilities on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Readily Available Market Prices [Member]
Loans
Agricultural	$ 0	$ 0	$ 0
Commercial and financial	0	0	0
Real Estate [Abstract]
Construction, land development and commercial	0	0	0
Mortgage, farmland	0	0	0
Mortgage, 1 to 4 family first liens	0	0	0
Mortgage, 1 to 4 family junior liens	0	0	0
Mortgage, multi-family	0	0	0
Mortgage, commercial	0	0	0
Loans to individuals	0	0	0
Total financial instrument assets	192,723	192,723	154,353
Observable Market Prices [Member]
Loans
Agricultural	0	0	0
Commercial and financial	0	0	0
Real Estate [Abstract]
Construction, land development and commercial	0	0	0
Mortgage, farmland	0	0	0
Mortgage, 1 to 4 family first liens	0	0	0
Mortgage, 1 to 4 family junior liens	0	0	0
Mortgage, multi-family	0	0	0
Mortgage, commercial	0	0	0
Loans to individuals	0	0	0
Total financial instrument assets	317,184	317,184	316,094
Company Determined Market Prices [Member]
Loans
Agricultural	79,007	79,007	86,229
Commercial and financial	210,339	210,339	212,244
Real Estate [Abstract]
Construction, land development and commercial	102,867	102,867	108,651
Mortgage, farmland	227,368	227,368	211,947
Mortgage, 1 to 4 family first liens	867,383	867,383	818,083
Mortgage, 1 to 4 family junior liens	143,265	143,265	142,180
Mortgage, multi-family	336,147	336,147	329,344
Mortgage, commercial	369,365	369,365	353,796
Loans to individuals	27,765	27,765	25,610
Total financial instrument assets	2,484,620	2,484,620	2,412,186
Nonrecurring Basis [Member]
Loans
Agricultural	1,401	1,401	4,704
Commercial and financial	2,039	2,039	1,555
Real Estate [Abstract]
Construction, 1 to 4 family residential	0	0	729
Construction, land development and commercial	701	701	0
Mortgage, farmland	3,964	3,964	7,190
Mortgage, 1 to 4 family first liens	6,232	6,232	5,548
Mortgage, 1 to 4 family junior liens	22	22	25
Mortgage, multi-family	6,180	6,180	6,397
Mortgage, commercial	1,502	1,502	1,063
Loans to individuals	0	0	0
Foreclosed assets	0	0	0
Total financial instrument assets	22,041	22,041	27,211
Total Losses	341	816	909
Nonrecurring Basis [Member] | Agricultural [Member]
Real Estate [Abstract]
Total Losses	0	63	127
Nonrecurring Basis [Member] | Commercial and financial [Member]
Real Estate [Abstract]
Total Losses	(14)	122	159
Nonrecurring Basis [Member] | Real Estate: Construction, 1 to 4 family residential [Member]
Real Estate [Abstract]
Total Losses	0	0	0
Nonrecurring Basis [Member] | Real Estate: Construction, land development and commercial [Member]
Real Estate [Abstract]
Total Losses	0	0	0
Nonrecurring Basis [Member] | Real Estate: Mortgage, farmland [Member]
Real Estate [Abstract]
Total Losses	0	0	0
Nonrecurring Basis [Member] | Real Estate: Mortgage, 1 to 4 family first liens [Member]
Real Estate [Abstract]
Total Losses	169	313	404
Nonrecurring Basis [Member] | Real Estate: Mortgage, 1 to 4 family junior liens [Member]
Real Estate [Abstract]
Total Losses	0	60	88
Nonrecurring Basis [Member] | Real Estate: Mortgage, multi-family [Member]
Real Estate [Abstract]
Total Losses	0	0	0
Nonrecurring Basis [Member] | Real Estate: Mortgage, commercial [Member]
Real Estate [Abstract]
Total Losses	186	258	111
Nonrecurring Basis [Member] | Loans to individuals [Member]
Real Estate [Abstract]
Total Losses	0	0	20
Nonrecurring Basis [Member] | Foreclosed assets [Member]
Real Estate [Abstract]
Total Losses	0	0	0
Nonrecurring Basis [Member] | Readily Available Market Prices [Member]
Loans
Agricultural	0	0	0
Commercial and financial	0	0	0
Real Estate [Abstract]
Construction, 1 to 4 family residential	0	0	0
Construction, land development and commercial	0	0	0
Mortgage, farmland	0	0	0
Mortgage, 1 to 4 family first liens	0	0	0
Mortgage, 1 to 4 family junior liens	0	0	0
Mortgage, multi-family	0	0	0
Mortgage, commercial	0	0	0
Loans to individuals	0	0	0
Foreclosed assets	0	0	0
Total financial instrument assets	0	0	0
Nonrecurring Basis [Member] | Observable Market Prices [Member]
Loans
Agricultural	0	0	0
Commercial and financial	0	0	0
Real Estate [Abstract]
Construction, 1 to 4 family residential	0	0	0
Construction, land development and commercial	0	0	0
Mortgage, farmland	0	0	0
Mortgage, 1 to 4 family first liens	0	0	0
Mortgage, 1 to 4 family junior liens	0	0	0
Mortgage, multi-family	0	0	0
Mortgage, commercial	0	0	0
Loans to individuals	0	0	0
Foreclosed assets	0	0	0
Total financial instrument assets	0	0	0
Nonrecurring Basis [Member] | Company Determined Market Prices [Member]
Loans
Agricultural	1,401	1,401	4,704
Commercial and financial	2,039	2,039	1,555
Real Estate [Abstract]
Construction, 1 to 4 family residential	0	0	729
Construction, land development and commercial	701	701	0
Mortgage, farmland	3,964	3,964	7,190
Mortgage, 1 to 4 family first liens	6,232	6,232	5,548
Mortgage, 1 to 4 family junior liens	22	22	25
Mortgage, multi-family	6,180	6,180	6,397
Mortgage, commercial	1,502	1,502	1,063
Loans to individuals	0	0	0
Foreclosed assets	0	0	0
Total financial instrument assets	$ 22,041	$ 22,041	$ 27,211

Stock Repurchase Program (Detai

Stock Repurchase Program (Details) - $ / shares	3 Months Ended	9 Months Ended		158 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Jul. 26, 2005
Equity [Abstract]
Maximum number of share authorized to repurchase under the program (in shares)					1,500,000
Common stock purchased during the period (in shares)	40,818	97,081	40,265	1,106,998
Average price per share (in dollars per share)	$ 58.54

Commitments and Contingencies_2

Commitments and Contingencies (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
State and political subdivisions [Member]
Concentration Risk [Line Items]
Investment in securities issued by state and political subdivisions within the state of Iowa	$ 76,180
Home equity loans [Member]
Firm loan commitments and unused portion of lines of credit [Abstract]
Total financial instrument liabilities with off-balance-sheet risk	60,442	$ 55,171
Credit cards [Member]
Firm loan commitments and unused portion of lines of credit [Abstract]
Total financial instrument liabilities with off-balance-sheet risk	52,882	49,235
Commercial, real estate and home construction [Member]
Firm loan commitments and unused portion of lines of credit [Abstract]
Total financial instrument liabilities with off-balance-sheet risk	104,426	117,021
Commercial lines and real estate purchase loans [Member]
Firm loan commitments and unused portion of lines of credit [Abstract]
Total financial instrument liabilities with off-balance-sheet risk	189,351	159,450
Outstanding letters of credit [Member]
Firm loan commitments and unused portion of lines of credit [Abstract]
Total financial instrument liabilities with off-balance-sheet risk	$ 7,841	$ 9,113

Income Taxes (Details)

Income Taxes (Details)	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Income Tax Examination [Line Items]
Effective tax rate	20.05%	30.48%
Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Income tax examination, years under examination	December 31, 2017, 2016, and 2015
State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Income tax examination, years under examination	December 31, 2017, 2016, and 2015

Derivative Financial Instrume_3

Derivative Financial Instruments (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)	Nov. 07, 2013USD ($)derivative
Derivatives, Fair Value [Line Items]
Owned and pledged as collateral	$ 930,000		$ 930,000
Gain (Loss) Recognized in Other Comprehensive Income, Net [Abstract]
Net change in unrealized income on derivatives	361,000	$ 259,000	1,887,000	$ 474,000
Interest Rate Swap 1 [Member] | Interest Expense [Member]
Gain (Loss) Recognized in Other Comprehensive Income, Net [Abstract]
Amount of Gain (Loss), Reclassified from AOCI into Income (Effective Portion)			0		$ 0
Interest Rate Swap 1 [Member] | Other Income [Member]
Gain (Loss) Recognized in Other Comprehensive Income, Net [Abstract]
Amount of Gain (Loss), Recognized in Income on Derivatives (Ineffective Portion)			0		0
Interest Rate Swap 1 [Member] | Other Liabilities [Member]
Derivative instrument according to type of hedges [Abstract]
Notional Amount	25,000,000		25,000,000		25,000,000	$ 25,000,000
Fair Value	26,000		$ 26,000		$ (582,000)
Maturity			Nov. 9, 2020		Nov. 9, 2020
Interest Rate Swap 1 [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Gain (Loss) Recognized in Other Comprehensive Income, Net [Abstract]
Net change in unrealized income on derivatives			$ 457,000		$ 318,000
Interest Rate Swap 2 [Member] | Interest Expense [Member]
Gain (Loss) Recognized in Other Comprehensive Income, Net [Abstract]
Amount of Gain (Loss), Reclassified from AOCI into Income (Effective Portion)			0		0
Interest Rate Swap 2 [Member] | Other Income [Member]
Gain (Loss) Recognized in Other Comprehensive Income, Net [Abstract]
Amount of Gain (Loss), Recognized in Income on Derivatives (Ineffective Portion)			0		0
Interest Rate Swap 2 [Member] | Other Liabilities [Member]
Derivative instrument according to type of hedges [Abstract]
Notional Amount	25,000,000		25,000,000		25,000,000	$ 25,000,000
Fair Value	$ (958,000)		$ (958,000)		$ (2,237,000)
Maturity			Nov. 7, 2023		Nov. 7, 2023
Interest Rate Swap 2 [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Gain (Loss) Recognized in Other Comprehensive Income, Net [Abstract]
Net change in unrealized income on derivatives			$ 960,000		$ 373,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Number of interest rate swaps held | derivative						2
Designated as Hedging Instrument [Member] | Interest Rate Swap 1 [Member]
Derivatives, Fair Value [Line Items]
Number of interest rate swaps held | derivative						1