General (Policies)	6 Months Ended
Jun. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	The consolidated financial statements include the accounts of Fauquier Bankshares, Inc. (the “Company”) and its wholly-owned subsidiary, The Fauquier Bank (the “Bank”), and the Bank’s wholly-owned subsidiaries, Fauquier Bank Services, Inc. and Specialty Properties Acquisitions - VA, LLC. Specialty Properties Acquisitions - VA, LLC was formed with the sole purpose of holding foreclosed property. The consolidated financial statements do not include the accounts of Fauquier Statutory Trust II, a wholly-owned subsidiary of the Company. In consolidation, significant intercompany financial balances and transactions have been eliminated. In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments (consisting of only normal recurring accruals) necessary to present fairly the financial position as of June 30, 2020 and the results of operations for the three and six months ended June 30, 2020 and 2019, in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The notes included herein should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s 2019 Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”). The results of operations for the three and six months ended June 30, 2020 and 2019 are not necessarily indicative of the results expected for the full year or any other interim period. Certain amounts in the 2019 consolidated financial statements have been reclassified to conform to the 2020 presentation. No reclassifications were significant and there was no effect on net income.
Significant Events	Significant Events On March 11, 2020, the World Health Organization declared the novel coronavirus (“COVID-19”) a pandemic as a result of the global spread of the illness. In response to the outbreak, federal and state authorities in the U.S. introduced various measures to try to limit or slow the spread of the virus, including travel restrictions, nonessential business closures, stay-at-home orders and strict social distancing. The full impact of COVID-19 is unknown and rapidly evolving. It has caused substantial disruption in international and U.S. economies, markets and employment. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) was enacted to, among other provisions, provide emergency assistance for individuals, families and businesses affected by COVID-19. The outbreak is having a significant adverse impact on certain industries the Company serves, including but not limited to, religious organizations, hospitality, childcare and restaurants. As of June 30, 2020, the Company’s aggregate exposure in these industries was $65.9 million, or 10.6% of total loans. Based on management’s current assessment of the increased inherent risk in the loan portfolio, the allowance for loan losses increased $1.2 million, or 22.4%, compared to December 31, 2019. The increase in the allowance for loan losses was in large part due to an increase in the qualitative factors related to COVID-19. Most notably, a $860,000 increase, was driven by the deteriorating economic conditions caused by COVID-19, including the increase in the unemployment rate for the Commonwealth of Virginia. Due to the significant uncertainties related to the ultimate duration of COVID-19, it is reasonably possible that estimates made in the financial statements could be materially and adversely impacted in the near term as a result of these conditions, including that the credit quality of the Company’s loan portfolio may decline and loan defaults could increase.
Recent Accounting Pronouncements and Other Regulatory Statements	Recent Accounting Pronouncements and Other Regulatory Statements In June 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The amendments, among other things, require the measurement of 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. In addition, the ASU amends the accounting for credit losses on available for sale debt securities and purchased financial assets with credit deterioration. The FASB has issued multiple updates to ASU 2016-13 as codified in Topic 326, including ASUs 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, and 2020-03. These ASUs have provided for various minor technical corrections and improvements to the codification as well as other transition matters. Smaller reporting companies who file with the SEC and all other entities who do not file with the SEC are required to apply the guidance for fiscal years, and interim periods within those years, beginning after December 15, 2022. Changes under ASU 2016-13 and subsequent updates represent a fundamental shift from existing GAAP and may result in a material increase to the Company's accounting for credit losses on financial instruments. To prepare for implementation of the new standard the Company has established a working group to evaluate the impact these changes will have on the Company’s financial statements and related disclosures. The Company has also contracted with a third-party for credit modeling in accordance with ASU 2016-13. The Company has focused on model validations, the development of processes and related controls, and the evaluation of parallel runs. The Company has not yet determined an estimate of the effect of these changes. Effective November 25, 2019, the SEC adopted Staff Accounting Bulletin (“SAB”) 119. SAB 119 updated portions of SEC interpretative guidance to align with FASB Accounting Standards Codification (“ASC”) 326, “Financial Instruments – Credit Losses.” The SAB covers topics including (i) measuring current expected credit losses; (ii) development, governance, and documentation of a systematic methodology; (iii) documenting the results of a systematic methodology; and (iv) validating a systematic methodology. In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820): “Changes to the Disclosure Requirements for Fair Value Measurement.” ASU 2018-13 modifies the disclosure requirements on fair value measurements by requiring that Level 3 fair value disclosures include the range and weighted average of significant unobservable inputs used to develop those fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. Certain disclosure requirements in Topic 820 were also removed or modified. ASU 2018-13 was effective for the Company on January 1, 2020. The Company does not expect the adoption of ASU 2018-13 to have a material impact on its consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans.” These amendments modify the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. Certain disclosure requirements have been deleted while the following disclosure requirements have been added: the weighted-average interest crediting rates for cash balance plans and other plans with promised interest crediting rates and an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. The amendments also clarify the disclosure requirements in paragraph 715-20-50-3, which state that the following information for defined benefit pension plans should be disclosed: The projected benefit obligation (“PBO”) and fair value of plan assets for plans with PBOs in excess of plan assets and the accumulated benefit obligation (“ABO”) and fair value of plan assets for plans with ABOs in excess of plan assets. The amendments are effective for fiscal years ending after December 15, 2020. Early adoption is permitted. The Company does not expect the adoption of ASU 2018-14 to have a material impact on its consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes.” The ASU is expected to reduce the cost and complexity related to the accounting for income taxes by removing specific exceptions to general principles in Topic 740 (eliminating the need for an organization to analyze whether certain exceptions apply in a given period) and improving financial statement preparers’ application of certain income tax-related guidance. This ASU is part of the FASB’s simplification initiative to make narrow-scope simplifications and improvements to accounting standards through a series of short-term projects. For public business entities, the amendments are effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact that ASU 2019-12 will have on its consolidated financial statements. In January 2020, the FASB issued ASU 2020-01, “Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) – Clarifying the Interactions between Topic 321, Topic 323, and Topic 815.” The ASU is based on a consensus of the Emerging Issues Task Force and is expected to increase comparability in accounting for these transactions. ASU 2016-01 made targeted improvements to accounting for financial instruments, including providing an entity the ability to measure certain equity securities without a readily determinable fair value at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. Among other topics, the amendments clarify that an entity should consider observable transactions that require it to either apply or discontinue the equity method of accounting. For public business entities, the amendments in the ASU are effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of ASU 2020-01 to have a material impact on its consolidated financial statements. In March 2020, the FASB issued ASU No. 2020-04 “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” These amendments provide temporary optional guidance to ease the potential burden in accounting for reference rate reform. The ASU provides optional expedients and exceptions for applying GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference London Inter-bank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued. It is intended to help stakeholders during the global market-wide reference rate transition period. The guidance is effective for all entities as of March 12, 2020 through December 31, 2022. The Company is currently evaluating the impact of the reference rate reform on the Company’s consolidated financial statements. On June 28, 2018, the SEC adopted amendments to the definition of “smaller reporting company” that were effective on September 10, 2018. Under the new definition, generally, a company qualifies as a “smaller reporting company” if (i) it has public float of less than $250 million or (ii) it has less than $100 million in annual revenues and (a) no public float or (b) public float of less than $700 million. Because of the Company’s public float being less than $250 million as of the measurement date in 2019, the Company is considered a smaller reporting company with respect to its SEC filings. On March 12, 2020, the SEC finalized amendments to its definitions of “accelerated filer” and “large accelerated filer.” The amendments increase the threshold criteria for meeting these filer classifications and are effective on April 27, 2020. Any changes in filer status are to be applied beginning with the filer’s first annual report filed with the SEC subsequent to the effective date. For the Company, this will be its annual report on Form 10-K with respect to the year ending December 31, 2020. Pursuant to Section 404(b) of the Sarbanes-Oxley Act, the classifications of “accelerated filer” and “large accelerated filer” require a public company to obtain an external auditor attestation concerning the effectiveness of a company’s internal control over financial reporting (“ICFR”) and include the opinion on ICFR in its annual report on Form 10-K. The Company has complied with such requirements during the years it was considered an accelerated filer. The SEC’s 2020 definition amendments exclude from the accelerated filer and large accelerated filer definitions an issuer that (i) is eligible to be a smaller reporting company and (ii) had annual revenues of less than $100 million in the most recent fiscal year. Such entity can now be considered a “non-accelerated filer.” With respect to the 2020 fiscal year, the Company expects to continue to be a smaller reporting company and no longer be considered an accelerated filer. This would mean the Company would not be required to obtain the external auditor attestation of its ICFR. If the Company’s annual revenues exceed $100 million, its category may change back to that of an accelerated filer. Non-accelerated filers have additional time to file quarterly and annual financial statements. In March 2020 (revised in April 2020), various regulatory agencies, including the Board of Governors of the Federal Reserve System and the Federal Deposit Insurance Corporation (“the agencies”), issued an interagency statement on loan modifications and reporting for financial institutions working with customers affected by COVID-19. The interagency statement was effective immediately and impacted accounting for loan modifications. Under ASC 310-40, “Receivables - Troubled Debt Restructurings by Creditors,” a restructuring of debt constitutes a troubled debt restructuring (“TDR”) if the creditor, for economic or legal reasons related to the debtor’s financial difficulties, grants a concession to the debtor that it would not otherwise consider. The agencies confirmed with the staff of the FASB that short-term modifications made on a good faith basis in response to COVID-19 to borrowers who were current prior to any relief, are not to be considered TDRs. This includes short-term modifications such as payment deferrals, fee waivers, extensions of repayment terms, or other delays in payment that are insignificant. Borrowers considered current are those that are less than 30 days past due on their contractual payments at the time a modification program is implemented. See Note 3 of the consolidated financial statements for additional disclosure of TDRs as of June 30, 2020.

General (Policies)

6 Months Ended

Jun. 30, 2020

Organization Consolidation And Presentation Of Financial Statements [Abstract]

The consolidated financial statements include the accounts of Fauquier Bankshares, Inc. (the “Company”) and its wholly-owned subsidiary, The Fauquier Bank (the “Bank”), and the Bank’s wholly-owned subsidiaries, Fauquier Bank Services, Inc. and Specialty Properties Acquisitions - VA, LLC. Specialty Properties Acquisitions - VA, LLC was formed with the sole purpose of holding foreclosed property. The consolidated financial statements do not include the accounts of Fauquier Statutory Trust II, a wholly-owned subsidiary of the Company. In consolidation, significant intercompany financial balances and transactions have been eliminated. In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments (consisting of only normal recurring accruals) necessary to present fairly the financial position as of June 30, 2020 and the results of operations for the three and six months ended June 30, 2020 and 2019, in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The notes included herein should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s 2019 Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”).

The results of operations for the three and six months ended June 30, 2020 and 2019 are not necessarily indicative of the results expected for the full year or any other interim period.

Certain amounts in the 2019 consolidated financial statements have been reclassified to conform to the 2020 presentation. No reclassifications were significant and there was no effect on net income.

Significant Events

On March 11, 2020, the World Health Organization declared the novel coronavirus (“COVID-19”) a pandemic as a result of the global spread of the illness. In response to the outbreak, federal and state authorities in the U.S. introduced various measures to try to limit or slow the spread of the virus, including travel restrictions, nonessential business closures, stay-at-home orders and strict social distancing.

The full impact of COVID-19 is unknown and rapidly evolving. It has caused substantial disruption in international and U.S. economies, markets and employment. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (the “CARES Act”) was enacted to, among other provisions, provide emergency assistance for individuals, families and businesses affected by COVID-19.

The outbreak is having a significant adverse impact on certain industries the Company serves, including but not limited to, religious organizations, hospitality, childcare and restaurants. As of June 30, 2020, the Company’s aggregate exposure in these industries was $65.9 million, or 10.6% of total loans. Based on management’s current assessment of the increased inherent risk in the loan portfolio, the allowance for loan losses increased $1.2 million, or 22.4%, compared to December 31, 2019. The increase in the allowance for loan losses was in large part due to an increase in the qualitative factors related to COVID-19. Most notably, a $860,000 increase, was driven by the deteriorating economic conditions caused by COVID-19, including the increase in the unemployment rate for the Commonwealth of Virginia.

Due to the significant uncertainties related to the ultimate duration of COVID-19, it is reasonably possible that estimates made in the financial statements could be materially and adversely impacted in the near term as a result of these conditions, including that the credit quality of the Company’s loan portfolio may decline and loan defaults could increase.

Recent Accounting Pronouncements and Other Regulatory Statements

In June 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The amendments, among other things, require the measurement of 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. In addition, the ASU amends the accounting for credit losses on

available for sale debt securities and purchased financial assets with credit deterioration. The FASB has issued multiple updates to ASU 2016-13 as codified in Topic 326, including ASUs 2019-04, 2019-05, 2019-10, 2019-11, 2020-02, and 2020-03. These ASUs have provided for various minor technical corrections and improvements to the codification as well as other transition matters. Smaller reporting companies who file with the SEC and all other entities who do not file with the SEC are required to apply the guidance for fiscal years, and interim periods within those years, beginning after December 15, 2022. Changes under ASU 2016-13 and subsequent updates represent a fundamental shift from existing GAAP and may result in a material increase to the Company's accounting for credit losses on financial instruments. To prepare for implementation of the new standard the Company has established a working group to evaluate the impact these changes will have on the Company’s financial statements and related disclosures. The Company has also contracted with a third-party for credit modeling in accordance with ASU 2016-13. The Company has focused on model validations, the development of processes and related controls, and the evaluation of parallel runs. The Company has not yet determined an estimate of the effect of these changes.

Effective November 25, 2019, the SEC adopted Staff Accounting Bulletin (“SAB”) 119. SAB 119 updated portions of SEC interpretative guidance to align with FASB Accounting Standards Codification (“ASC”) 326, “Financial Instruments – Credit Losses.” The SAB covers topics including (i) measuring current expected credit losses; (ii) development, governance, and documentation of a systematic methodology; (iii) documenting the results of a systematic methodology; and (iv) validating a systematic methodology.

In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820): “Changes to the Disclosure Requirements for Fair Value Measurement.” ASU 2018-13 modifies the disclosure requirements on fair value measurements by requiring that Level 3 fair value disclosures include the range and weighted average of significant unobservable inputs used to develop those fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. Certain disclosure requirements in Topic 820 were also removed or modified. ASU 2018-13 was effective for the Company on January 1, 2020. The Company does not expect the adoption of ASU 2018-13 to have a material impact on its consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans.” These amendments modify the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. Certain disclosure requirements have been deleted while the following disclosure requirements have been added: the weighted-average interest crediting rates for cash balance plans and other plans with promised interest crediting rates and an explanation of the reasons for significant gains and losses related to changes in the benefit obligation for the period. The amendments also clarify the disclosure requirements in paragraph 715-20-50-3, which state that the following information for defined benefit pension plans should be disclosed: The projected benefit obligation (“PBO”) and fair value of plan assets for plans with PBOs in excess of plan assets and the accumulated benefit obligation (“ABO”) and fair value of plan assets for plans with ABOs in excess of plan assets. The amendments are effective for fiscal years ending after December 15, 2020. Early adoption is permitted. The Company does not expect the adoption of ASU 2018-14 to have a material impact on its consolidated financial statements.

In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes.” The ASU is expected to reduce the cost and complexity related to the accounting for income taxes by removing specific exceptions to general principles in Topic 740 (eliminating the need for an organization to analyze whether certain exceptions apply in a given period) and improving financial statement preparers’ application of certain income tax-related guidance. This ASU is part of the FASB’s simplification initiative to make narrow-scope simplifications and improvements to accounting standards through a series of short-term projects. For public business entities, the amendments are effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently assessing the impact that ASU 2019-12 will have on its consolidated financial statements.

In January 2020, the FASB issued ASU 2020-01, “Investments - Equity Securities (Topic 321), Investments - Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815) – Clarifying the Interactions between Topic 321, Topic 323, and Topic 815.” The ASU is based on a consensus of the Emerging Issues Task Force and is expected to increase comparability in accounting for these transactions. ASU 2016-01 made targeted improvements to accounting for financial instruments, including providing an entity the ability to measure certain equity securities without a readily determinable fair

value at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. Among other topics, the amendments clarify that an entity should consider observable transactions that require it to either apply or discontinue the equity method of accounting. For public business entities, the amendments in the ASU are effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted. The Company does not expect the adoption of ASU 2020-01 to have a material impact on its consolidated financial statements.

In March 2020, the FASB issued ASU No. 2020-04 “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting.” These amendments provide temporary optional guidance to ease the potential burden in accounting for reference rate reform. The ASU provides optional expedients and exceptions for applying GAAP to contract modifications and hedging relationships, subject to meeting certain criteria, that reference London Inter-bank Offered Rate (“LIBOR”) or another reference rate expected to be discontinued. It is intended to help stakeholders during the global market-wide reference rate transition period. The guidance is effective for all entities as of March 12, 2020 through December 31, 2022. The Company is currently evaluating the impact of the reference rate reform on the Company’s consolidated financial statements.

On June 28, 2018, the SEC adopted amendments to the definition of “smaller reporting company” that were effective on September 10, 2018. Under the new definition, generally, a company qualifies as a “smaller reporting company” if (i) it has public float of less than $250 million or (ii) it has less than $100 million in annual revenues and (a) no public float or (b) public float of less than $700 million. Because of the Company’s public float being less than $250 million as of the measurement date in 2019, the Company is considered a smaller reporting company with respect to its SEC filings. On March 12, 2020, the SEC finalized amendments to its definitions of “accelerated filer” and “large accelerated filer.” The amendments increase the threshold criteria for meeting these filer classifications and are effective on April 27, 2020. Any changes in filer status are to be applied beginning with the filer’s first annual report filed with the SEC subsequent to the effective date. For the Company, this will be its annual report on Form 10-K with respect to the year ending December 31, 2020. Pursuant to Section 404(b) of the Sarbanes-Oxley Act, the classifications of “accelerated filer” and “large accelerated filer” require a public company to obtain an external auditor attestation concerning the effectiveness of a company’s internal control over financial reporting (“ICFR”) and include the opinion on ICFR in its annual report on Form 10-K. The Company has complied with such requirements during the years it was considered an accelerated filer. The SEC’s 2020 definition amendments exclude from the accelerated filer and large accelerated filer definitions an issuer that (i) is eligible to be a smaller reporting company and (ii) had annual revenues of less than $100 million in the most recent fiscal year. Such entity can now be considered a “non-accelerated filer.” With respect to the 2020 fiscal year, the Company expects to continue to be a smaller reporting company and no longer be considered an accelerated filer. This would mean the Company would not be required to obtain the external auditor attestation of its ICFR. If the Company’s annual revenues exceed $100 million, its category may change back to that of an accelerated filer. Non-accelerated filers have additional time to file quarterly and annual financial statements.

In March 2020 (revised in April 2020), various regulatory agencies, including the Board of Governors of the Federal Reserve System and the Federal Deposit Insurance Corporation (“the agencies”), issued an interagency statement on loan modifications and reporting for financial institutions working with customers affected by COVID-19. The interagency statement was effective immediately and impacted accounting for loan modifications. Under ASC 310-40, “Receivables - Troubled Debt Restructurings by Creditors,” a restructuring of debt constitutes a troubled debt restructuring (“TDR”) if the creditor, for economic or legal reasons related to the debtor’s financial difficulties, grants a concession to the debtor that it would not otherwise consider. The agencies confirmed with the staff of the FASB that short-term modifications made on a good faith basis in response to COVID-19 to borrowers who were current prior to any relief, are not to be considered TDRs. This includes short-term modifications such as payment deferrals, fee waivers, extensions of repayment terms, or other delays in payment that are insignificant. Borrowers considered current are those that are less than 30 days past due on their contractual payments at the time a modification program is implemented. See Note 3 of the consolidated financial statements for additional disclosure of TDRs as of June 30, 2020.