Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS Principles of Consolidation: Farmers National Banc Corp. (“Company”) is a Financial Holding Company registered under the Bank Holding Company Act of 1956, as amended. The Company provides full banking services through its nationally chartered subsidiary, The Farmers National Bank of Canfield (“Bank”). The Bank acquired Bowers Insurance Agency, Inc. (“Bowers”) and consolidated the activity of the Bowers with Farmers National Insurance (“Insurance”) during 2016. The Company acquired First National Bank of Orrville (“First National Bank”) a subsidiary of National Bancshares Corporation (“NBOH”) and 1^st National Community Bank (“FNCB”), a subsidiary of Tri-State 1^st Banc, Inc. (“Tri-State”) during 2015 and consolidated all activity of both acquisitions within the Bank. Farmers National Captive, Inc. (“Captive”) was formed during the third quarter of 2016 and is a wholly-owned insurance subsidiary of the Company that provides property and casualty insurance coverage to the Company and its subsidiaries. The Captive pools resources with thirteen other similar insurance company subsidiaries of financial institutions to spread a limited amount of risk among themselves and to provide insurance where not currently available or economically feasible in today’s insurance market place. The consolidated financial statements also include the accounts of the Bank’s subsidiaries; Insurance and Farmers of Canfield Investment Co. (“Investments”). The Company provides trust services through its subsidiary, Farmers Trust Company (“Trust”), retirement consulting services through National Associates, Inc. (“NAI”) and insurance services through the Bank’s subsidiary, Insurance. The consolidated financial statements include the accounts of the Company, the Bank and its subsidiaries, along with the Trust, NAI and Captive. All significant intercompany balances and transactions have been eliminated in the consolidation. Basis of Presentation: The unaudited condensed consolidated financial statements have been prepared in conformity with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. generally accepted accounting principles (“U.S. GAAP”) for complete financial statements. The financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s 2016 Annual Report to Shareholders included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. The interim consolidated financial statements include all adjustments (consisting of only normal recurring items) that, in the opinion of management, are necessary for a fair presentation of the financial position and results of operations for the periods presented. The results of operations for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year. Certain items included in the prior period financial statements were reclassified to conform to the current period presentation. There was no effect on net income or total stockholders’ equity. Estimates: The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Segments: The Company provides a broad range of financial services to individuals and companies in northeastern Ohio. Operations are managed and financial performance is primarily aggregated and reported in three lines of business, the Bank segment, the Trust segment and the Retirement Consulting segment. Comprehensive Income: Comprehensive income consists of net income and other comprehensive income. Other comprehensive income consists of unrealized gains and losses on securities available for sale and changes in the funded status of the post-retirement health plan, which are recognized as separate components of equity, net of tax effects. For all periods presented there was no change in the funded status of the post-retirement health plan. New Accounting Standards: During April of 2017, the FASB issued ASU 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. Under current U.S. GAAP, a premium is typically amortized to the maturity date when a callable debt security is purchased at a premium, even if the holder is certain the call will be exercised. As a result, upon the exercise of a call on a callable debt security held at a premium, the unamortized premium is recorded as a loss in earnings. The new standard shortens the amortization period for the premium to the earliest call date to more closely align interest income recorded on bonds held at a premium or a discount with the economics of the underlying instrument. The standard takes effect for public business entities for fiscal years and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. The Company amortizes the premium to the expected call date currently and does not expect the adoption of this ASU to have an impact on its Consolidated Financial Statements. In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This ASU eliminates Step 2 from the goodwill impairment test. Instead, under the new guidance, an entity is to perform its annual goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge would be recognized for the amount by which the carrying amount exceeds the reporting unit's fair value. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance is not expected to have an impact on the Company's Consolidated Financial Statements. In June 2016, the FASB issued ASU 2016-13: Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU requires an organization to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. Organizations will continue to use judgment to determine which loss estimation method is appropriate for their circumstances. Additionally, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for public companies for annual periods beginning after December 15, 2019, including interim periods within those fiscal years. Entities will apply the standard's provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The Company has begun to accumulate historical credit information and created a task force in preparation for the adoption of ASU 2016-13, but management has not determined the full impact the new standard will have on the Consolidated Financial Statements. In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09: Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendments in ASU 2016-09 simplify several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. ASU 2016-09 is effective for public companies for interim and annual reporting periods beginning after December 15, 2016, with early adoption permitted. The Company adopted the ASU 2016-09 on January 1, 2017 which had no material impact on the Consolidated Financial Statements and disclosures. In February 2016, FASB issued ASU 2016-02 (Topic 842): Leases. The main objective of ASU 2016-02 is to provide users with useful, transparent, and complete information about leasing transactions. ASU 2016-02 requires the rights and obligations associated with leasing arrangements be reflected on the balance sheet in order to increase transparency and comparability among organizations. Under the updated guidance, lessees will be required to recognize a right-to-use asset and a liability to make a lease payment and disclose key information about leasing arrangements. ASU 2016-02 is effective for public companies for interim and annual reporting periods beginning after December 15, 2018, with early adoption permitted. The Company expects the adoption of this ASU could require capitalization of certain leases in the amount of $2.6 million on the balance sheet as an asset and a related liability of equal amount with no income statement affect. Therefore the Company does not expect the adoption of this ASU to have a material impact to its Consolidated Financial Statements. In January 2016, FASB issued ASU 2016-01: Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The main objective of ASU 2016-01 is to enhance the reporting model for financial instruments to provide users of financial statements with more decision-useful information. ASU 2016-01 addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. Some of the amendments in ASU 2016-01 include the following: 1) Require equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income; 2) Simplify the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; 3) Require public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; and 4) Require an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value; among others. The amendments of ASU 2016-01 are effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Management anticipates the impact of the adoption of this guidance on the Company’s consolidated financial statements to be limited. In May 2014, FASB issued ASU 2014-09: Revenue from Contracts with Customers (Topic 606). The ASU creates a new topic, Topic 606, to provide guidance on revenue recognition for entities that enter into contracts with customers to transfer goods or services or enter into contracts for the transfer of nonfinancial assets. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Additional disclosures are required to provide quantitative and qualitative information regarding the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016. Management anticipates the impact of the adoption of this guidance on the Company’s consolidated financial statements to be limited. There will be no impact to core revenue which is mainly interest income less interest expense. Management is still assessing the impact from other non-interest income sources, specifically, deposit fees, trust income and retirement consulting income.

NOTES TO UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS

Principles of Consolidation:

Farmers National Banc Corp. (“Company”) is a Financial Holding Company registered under the Bank Holding Company Act of 1956, as amended. The Company provides full banking services through its nationally chartered subsidiary, The Farmers National Bank of Canfield (“Bank”). The Bank acquired Bowers Insurance Agency, Inc. (“Bowers”) and consolidated the activity of the Bowers with Farmers National Insurance (“Insurance”) during 2016. The Company acquired First National Bank of Orrville (“First National Bank”) a subsidiary of National Bancshares Corporation (“NBOH”) and 1^st National Community Bank (“FNCB”), a subsidiary of Tri-State 1^st Banc, Inc. (“Tri-State”) during 2015 and consolidated all activity of both acquisitions within the Bank. Farmers National Captive, Inc. (“Captive”) was formed during the third quarter of 2016 and is a wholly-owned insurance subsidiary of the Company that provides property and casualty insurance coverage to the Company and its subsidiaries. The Captive pools resources with thirteen other similar insurance company subsidiaries of financial institutions to spread a limited amount of risk among themselves and to provide insurance where not currently available or economically feasible in today’s insurance market place. The consolidated financial statements also include the accounts of the Bank’s subsidiaries; Insurance and Farmers of Canfield Investment Co. (“Investments”). The Company provides trust services through its subsidiary, Farmers Trust Company (“Trust”), retirement consulting services through National Associates, Inc. (“NAI”) and insurance services through the Bank’s subsidiary, Insurance. The consolidated financial statements include the accounts of the Company, the Bank and its subsidiaries, along with the Trust, NAI and Captive. All significant intercompany balances and transactions have been eliminated in the consolidation.

Basis of Presentation:

The unaudited condensed consolidated financial statements have been prepared in conformity with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by U.S. generally accepted accounting principles (“U.S. GAAP”) for complete financial statements. The financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s 2016 Annual Report to Shareholders included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. The interim consolidated financial statements include all adjustments (consisting of only normal recurring items) that, in the opinion of management, are necessary for a fair presentation of the financial position and results of operations for the periods presented. The results of operations for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year. Certain items included in the prior period financial statements were reclassified to conform to the current period presentation. There was no effect on net income or total stockholders’ equity.

Estimates:

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Segments:

The Company provides a broad range of financial services to individuals and companies in northeastern Ohio. Operations are managed and financial performance is primarily aggregated and reported in three lines of business, the Bank segment, the Trust segment and the Retirement Consulting segment.

Comprehensive Income:

Comprehensive income consists of net income and other comprehensive income. Other comprehensive income consists of unrealized gains and losses on securities available for sale and changes in the funded status of the post-retirement health plan, which are recognized as separate components of equity, net of tax effects. For all periods presented there was no change in the funded status of the post-retirement health plan.

New Accounting Standards:

During April of 2017, the FASB issued ASU 2017-08, Receivables—Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. Under current U.S. GAAP, a premium is typically amortized to the maturity date when a callable debt security is purchased at a premium, even if the holder is certain the call will be exercised. As a result, upon the exercise of a call on a callable debt security held at a premium, the unamortized premium is recorded as a loss in earnings. The new standard shortens the amortization period for the premium to the earliest call date to more closely align interest income recorded on bonds held at a premium or a discount with the economics of the underlying instrument. The standard takes effect for public business entities for fiscal years and interim periods within those fiscal years, beginning after December 15, 2018. Early adoption is permitted, including adoption in an interim period. The Company amortizes the premium to the expected call date currently and does not expect the adoption of this ASU to have an impact on its Consolidated Financial Statements.

In January 2017, the FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. This ASU eliminates Step 2 from the goodwill impairment test. Instead, under the new guidance, an entity is to perform its annual goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An impairment charge would be recognized for the amount by which the carrying amount exceeds the reporting unit's fair value. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The adoption of this guidance is not expected to have an impact on the Company's Consolidated Financial Statements.

In June 2016, the FASB issued ASU 2016-13: Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU requires an organization to measure all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. Financial institutions and other organizations will now use forward-looking information to better inform their credit loss estimates. Many of the loss estimation techniques applied today will still be permitted, although the inputs to those techniques will change to reflect the full amount of expected credit losses. Organizations will continue to use judgment to determine which loss estimation method is appropriate for their circumstances. Additionally, the ASU amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 is effective for public companies for annual periods beginning after December 15, 2019, including interim periods within those fiscal years. Entities will apply the standard's provisions as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The Company has begun to accumulate historical credit information and created a task force in preparation for the adoption of ASU 2016-13, but management has not determined the full impact the new standard will have on the Consolidated Financial Statements.

In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09: Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The amendments in ASU 2016-09 simplify several aspects of the accounting for employee share-based payment transactions, including the accounting for income taxes, forfeitures and statutory tax withholding requirements, as well as classification in the statement of cash flows. ASU 2016-09 is effective for public companies for interim and annual reporting periods beginning after December 15, 2016, with early adoption permitted. The Company adopted the ASU 2016-09 on January 1, 2017 which had no material impact on the Consolidated Financial Statements and disclosures.

In February 2016, FASB issued ASU 2016-02 (Topic 842): Leases. The main objective of ASU 2016-02 is to provide users with useful, transparent, and complete information about leasing transactions. ASU 2016-02 requires the rights and obligations associated with leasing arrangements be reflected on the balance sheet in order to increase transparency and comparability among organizations. Under the updated guidance, lessees will be required to recognize a right-to-use asset and a liability to make a lease payment and disclose key information about leasing arrangements. ASU 2016-02 is effective for public companies for interim and annual reporting periods beginning after December 15, 2018, with early adoption permitted. The Company expects the adoption of this ASU could require capitalization of certain leases in the amount of $2.6 million on the balance sheet as an asset and a related liability of equal amount with no income statement affect. Therefore the Company does not expect the adoption of this ASU to have a material impact to its Consolidated Financial Statements.

In January 2016, FASB issued ASU 2016-01: Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The main objective of ASU 2016-01 is to enhance the reporting model for financial instruments to provide users of financial statements with more decision-useful information. ASU 2016-01 addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. Some of the amendments in ASU 2016-01 include the following: 1) Require equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income; 2) Simplify the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; 3) Require public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; and 4) Require an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value; among others. The amendments of ASU 2016-01 are effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Management anticipates the impact of the adoption of this guidance on the Company’s consolidated financial statements to be limited.

In May 2014, FASB issued ASU 2014-09: Revenue from Contracts with Customers (Topic 606). The ASU creates a new topic, Topic 606, to provide guidance on revenue recognition for entities that enter into contracts with customers to transfer goods or services or enter into contracts for the transfer of nonfinancial assets. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Additional disclosures are required to provide quantitative and qualitative information regarding the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers. The new guidance is effective for annual reporting periods, and interim reporting periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted only as of annual reporting periods beginning after December 15, 2016. Management anticipates the impact of the adoption of this guidance on the Company’s consolidated financial statements to be limited. There will be no impact to core revenue which is mainly interest income less interest expense. Management is still assessing the impact from other non-interest income sources, specifically, deposit fees, trust income and retirement consulting income.