Presentation of Financial Information	3 Months Ended
Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Presentation of Financial Information	Presentation of Financial Information Interim Financial Information (Unaudited): The financial information in this report for March 31, 2019 and March 31, 2018 has not been audited. The information included herein should be read in conjunction with the Company’s annual consolidated financial statements and footnotes included in the Company's most recent Annual Report on Form 10-K. The consolidated financial statements presented herein conform to U.S. generally accepted accounting principles and to general industry practices. In the opinion of SmartFinancial’s management, the accompanying interim financial statements contain all material adjustments necessary to present fairly the Company's financial condition, the results of operations, and cash flows for the interim period. Results for interim periods are not necessarily indicative of the results to be expected for a full year. Basis of Presentation and Accounting Estimates: All adjustments consisting of normal recurring accruals that in the opinion of management are necessary for a fair presentation of the financial position and the results of operations for the periods covered by the report have been included. The accompanying unaudited consolidated financial statements and related notes should be read in conjunction with those appearing in the most recent Annual Report previously filed on Form 10-K. The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All significant intercompany balances and transactions have been eliminated in consolidation. In preparing the consolidated financial statements in conformity with accounting principles generally accepted in the U.S, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet, and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Material estimates that are particularly susceptible to significant change in the near term relate to the determination of the allowance for loan losses, the valuation of foreclosed assets and deferred taxes, other than temporary impairments of securities, the fair value of financial instruments, goodwill, and business combination elements (Day 1 and Day 2 Valuation). Recently Issued and Adopted Accounting Pronouncements: As of January 1, 2019, the Company adopted certain accounting standard updates related to accounting for leases (Topic 842 - Leases), primarily Accounting Standards Update ASU 2016-02 and subsequent updates. Among other things, these updates require lessees to recognize a lease liability, measured on a discounted basis, related to the lessee's obligation to make lease payments arising under a lease contract; and a right-of-use asset related to the lessee's right to use, or control the use of, a specified asset for the lease term. The updates did not significantly change lease accounting requirements applicable to lessors and did not significantly impact the Company's consolidated financial statements in relation to contracts whereby the Company acts as a lessor. The Company adopted the updates using a modified-retrospective transition approach and recognized right-of-use lease assets and related lease liabilities totaling $2.3 million each as of January 1, 2019. As of March 31, 2019, right-of-use lease assets and related lease liabilities totaled $2.2 million each. In February 2016, the FASB issued ASU No. 2016-02, Leases. Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases): 1) a lease liability, which is the present value of a lessee’s obligation to make lease payments, and 2) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. Lessor accounting under the new guidance remains largely unchanged as it is substantially equivalent to existing guidance for sales-type leases, direct financing leases, and operating leases. Leveraged leases have been eliminated, although lessors can continue to account for existing leveraged leases using the current accounting guidance. Other limited changes were made to align lessor accounting with the lessee accounting model and the new revenue recognition standard. All entities will classify leases to determine how to recognize lease-related revenue and expense. Quantitative and qualitative disclosures will be required by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The intention is to require enough information to supplement the amounts recorded in the financial statements so that users can understand more about the nature of an entity’s leasing activities. ASU No. 2016-02 is effective for interim and annual reporting periods beginning after December 15, 2018. All entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. As the Company elected the transition option provided in ASU No. 2018-11 (see below), the modified retrospective approach was applied on January 1, 2019. Note 1. Presentation of Financial Information, Continued Recently Issued and Adopted Accounting Pronouncements (continued): The Company also elected certain relief options offered in ASU 2016-02 including the package of practical expedients, the option not to separate lease and non-lease components and instead to account for them as a single lease component, and the option not to recognize right-of-use assets and lease liabilities that arise from short-term leases (i.e., leases with terms of twelve months or less). We elected to apply certain practical adoption expedients provided under the updates whereby we did not reassess (i) whether any expired or existing contracts are or contain leases, (ii) the lease classification for any expired or existing leases and (iii) initial direct costs for any existing leases. The Company did not elect the hindsight practical expedient, which allows entities to use hindsight when determining lease term and impairment of right-of-use assets. The Company has several lease agreements, such as branch locations or office space, which are considered operating leases, and therefore, were not previously recognized on the Company’s consolidated balance sheet. The new guidance requires these lease agreements to be recognized on the consolidated balance sheet as a right-of-use asset and a corresponding lease liability. The new guidance did not have a material impact on the consolidated statements of income or the consolidated statements of cash flows. See Note 8 Leases for more information. In July 2018, the FASB issued ASU No. 2018-11, Leases - Targeted Improvements to provide entities with relief from the costs of implementing certain aspects of the new leasing standard, ASU No. 2016-02. Specifically, under the amendments in ASU 2018-11: (1) entities may elect not to recast the comparative periods presented when transitioning to the new leasing standard, and (2) lessors may elect not to separate lease and non-lease components when certain conditions are met. The amendments have the same effective date as ASU 2016-02 (January 1, 2019 for the Company). The Company adopted ASU 2018-11 on its required effective date of January 1, 2019 and elected both transition options mentioned above. As of January 1, 2019, the Company adopted ASU 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. The ASU expands the scope of Topic 718, Compensation-Stock Compensation (which previously only included payments to employees), to include share-based payment transactions for acquiring goods and services from non-employees. This required entities to apply the requirements of Topic 718 to non-employee awards, except for specific guidance on inputs to an option pricing model and the attribution of cost (i.e., the period of time over which share-based payment awards vest and the pattern of cost recognition over that period). Additionally, the amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in the grantor’s own operations by issuing share-based payment awards, and clarify that Topic 718 does not apply to share-based payments used to effectively provide (1) financing to the issuer, or (2) awards granted in conjunction with selling goods or services to customers as part of a contract accounted for under Topic 606, Revenue from Contracts with Customers. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. As of January 1, 2019, the Company adopted ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Topic 310-20): Premium Amortization on Purchased Callable Debt Securities. The ASU shortens the amortization period for certain callable debt securities held at a premium. The premium on individual callable debt securities shall be amortized to the earliest call date. This guidance does not apply to securities for which prepayments are estimated on a large number of similar loans where prepayments are probable and reasonably estimable. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements. Recently Issued Not Yet Effective Accounting Pronouncements: During interim periods, the Company follows the accounting policies set forth in its annual audited financial statements for the year ended December 31, 2018 as filed with the Securities and Exchange Commission. The following is a summary of recent authoritative pronouncements issued since December 31, 2018 but not yet effective that could impact the accounting, reporting, and/or disclosure of financial information by the Company . Note 1. Presentation of Financial Information, Continued Recently Not Yet Effective Accounting Pronouncements (continued): In June 2016, FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU changed the credit loss model on financial instruments measured at amortized cost, available for sale securities and certain purchased financial instruments. Credit losses on financial instruments measured at amortized cost will be determined using a current expected credit loss model which requires the Company to measure all expected credit losses for financial instruments held at the reporting date based on historical experience, current conditions, and reasonable supportable forecasts. This replaces the existing incurred loss model and is applicable to the measurement of credit losses on financial assets measured at amortized cost and applies to some off-balance sheet credit exposures. Purchased financial assets with more-than-insignificant credit deterioration since origination ("PCD assets" which are currently named "PCI Loans") measured at amortized cost will have an allowance for credit losses established at acquisition as part of the purchase price. Subsequent increases or decreases to the allowance for credit losses on PCD assets will be recognized in the income statement. Interest income should be recognized on PCD assets based on the effective interest rate, determined excluding the discount attributed to credit losses at acquisition. Credit losses relating to available-for-sale debt securities will be recognized through an allowance for credit losses. The amount of the credit loss is limited to the amount by which fair value is below amortized cost of the available-for-sale debt security. The amendments in this update are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years for the Company and other SEC filers. Early adoption is permitted and if early adopted, all provisions must be adopted in the same period. The amendments should be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the period adopted. A prospective approach is required for securities with other than temporary impairment recognized prior to adoption. The Company is continuing its implementation efforts through its company-wide implementation team. The implementation team meets periodically to discuss the latest developments and ensure progress is being made. The team also keeps current on evolving interpretations and industry practices related to ASU 2016-13 via webcasts, publications, conferences, and peer bank meetings. The team continues to evaluate and validate data resources and different loss methodologies. The Company’s preliminary evaluation indicates the provisions of ASU No. 2016-13 are expected to impact the Company’s consolidated financial statements, in particular an increase to the level of the reserve for credit losses. However, the Company continues to evaluate the extent of the potential impact. The guidance of ASU 2016-13 was recently amended by ASU 2018-19, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, which changed the effective date for non-public companies and clarified that operating lease receivables are not within the scope of the standard. Reclassifications: Certain captions and amounts in the 2018 consolidated financial statements were reclassified to conform to the 2019 presentation and these reclassifications had no impact on net income or shareholders' equity as previously reported. Earnings per common share: Basic earnings per common share represents income available to common shareholders divided by the weighted-average number of common shares outstanding during the period. Diluted earnings per common share reflects additional common shares that would have been outstanding if dilutive potential common shares had been issued, as well as any adjustment to income that would result from the assumed issuance (excluding tax impact). Potential common shares that may be issued by the Company relate solely to outstanding stock options, determined using the treasury stock method, and restricted stock awards, determined by the fair value of the Company's stock on date of grant.

Presentation of Financial Information

Interim Financial Information (Unaudited):

The financial information in this report for March 31, 2019 and March 31, 2018 has not been audited. The information included herein should be read in conjunction with the Company’s annual consolidated financial statements and footnotes included in the Company's most recent Annual Report on Form 10-K. The consolidated financial statements presented herein conform to U.S. generally accepted accounting principles and to general industry practices. In the opinion of SmartFinancial’s management, the accompanying interim financial statements contain all material adjustments necessary to present fairly the Company's financial condition, the results of operations, and cash flows for the interim period. Results for interim periods are not necessarily indicative of the results to be expected for a full year.

Basis of Presentation and Accounting Estimates:

All adjustments consisting of normal recurring accruals that in the opinion of management are necessary for a fair presentation of the financial position and the results of operations for the periods covered by the report have been included. The accompanying unaudited consolidated financial statements and related notes should be read in conjunction with those appearing in the most recent Annual Report previously filed on Form 10-K.

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary. All significant intercompany balances and transactions have been eliminated in consolidation.

In preparing the consolidated financial statements in conformity with accounting principles generally accepted in the U.S, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet, and reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

Material estimates that are particularly susceptible to significant change in the near term relate to the determination of the allowance for loan losses, the valuation of foreclosed assets and deferred taxes, other than temporary impairments of securities, the fair value of financial instruments, goodwill, and business combination elements (Day 1 and Day 2 Valuation).

Recently Issued and Adopted Accounting Pronouncements:

As of January 1, 2019, the Company adopted certain accounting standard updates related to accounting for leases (Topic 842 - Leases), primarily Accounting Standards Update ASU 2016-02 and subsequent updates. Among other things, these updates require lessees to recognize a lease liability, measured on a discounted basis, related to the lessee's obligation to make lease payments arising under a lease contract; and a right-of-use asset related to the lessee's right to use, or control the use of, a specified asset for the lease term. The updates did not significantly change lease accounting requirements applicable to lessors and did not significantly impact the Company's consolidated financial statements in relation to contracts whereby the Company acts as a lessor. The Company adopted the updates using a modified-retrospective transition approach and recognized right-of-use lease assets and related lease liabilities totaling $2.3 million each as of January 1, 2019. As of March 31, 2019, right-of-use lease assets and related lease liabilities totaled $2.2 million each.

In February 2016, the FASB issued ASU No. 2016-02, Leases. Under the new guidance, lessees will be required to recognize the following for all leases (with the exception of short-term leases): 1) a lease liability, which is the present value of a lessee’s obligation to make lease payments, and 2) a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. Lessor accounting under the new guidance remains largely unchanged as it is substantially equivalent to existing guidance for sales-type leases, direct financing leases, and operating leases. Leveraged leases have been eliminated, although lessors can continue to account for existing leveraged leases using the current accounting guidance. Other limited changes were made to align lessor accounting with the lessee accounting model and the new revenue recognition standard. All entities will classify leases to determine how to recognize lease-related revenue and expense. Quantitative and qualitative disclosures will be required by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing, and uncertainty of cash flows arising from leases. The intention is to require enough information to supplement the amounts recorded in the financial statements so that users can understand more about the nature of an entity’s leasing activities. ASU No. 2016-02 is effective for interim and annual reporting periods beginning after December 15, 2018. All entities are required to use a modified retrospective approach for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. As the Company elected the transition option provided in ASU No. 2018-11 (see below), the modified retrospective approach was applied on January 1, 2019.

Note 1. Presentation of Financial Information, Continued

Recently Issued and Adopted Accounting Pronouncements (continued):

The Company also elected certain relief options offered in ASU 2016-02 including the package of practical expedients, the option not to separate lease and non-lease components and instead to account for them as a single lease component, and the option not to recognize right-of-use assets and lease liabilities that arise from short-term leases (i.e., leases with terms of twelve months or less). We elected to apply certain practical adoption expedients provided under the updates whereby we did not reassess (i) whether any expired or existing contracts are or contain leases, (ii) the lease classification for any expired or existing leases and (iii) initial direct costs for any existing leases. The Company did not elect the hindsight practical expedient, which allows entities to use hindsight when determining lease term and impairment of right-of-use assets. The Company has several lease agreements, such as branch locations or office space, which are considered operating leases, and therefore, were not previously recognized on the Company’s consolidated balance sheet. The new guidance requires these lease agreements to be recognized on the consolidated balance sheet as a right-of-use asset and a corresponding lease liability. The new guidance did not have a material impact on the consolidated statements of income or the consolidated statements of cash flows. See Note 8 Leases for more information.

In July 2018, the FASB issued ASU No. 2018-11, Leases - Targeted Improvements to provide entities with relief from the costs of implementing certain aspects of the new leasing standard, ASU No. 2016-02. Specifically, under the amendments in ASU 2018-11: (1) entities may elect not to recast the comparative periods presented when transitioning to the new leasing standard, and (2) lessors may elect not to separate lease and non-lease components when certain conditions are met. The amendments have the same effective date as ASU 2016-02 (January 1, 2019 for the Company). The Company adopted ASU 2018-11 on its required effective date of January 1, 2019 and elected both transition options mentioned above.

As of January 1, 2019, the Company adopted ASU 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. The ASU expands the scope of Topic 718, Compensation-Stock Compensation (which previously only included payments to employees), to include share-based payment transactions for acquiring goods and services from non-employees. This required entities to apply the requirements of Topic 718 to non-employee awards, except for specific guidance on inputs to an option pricing model and the attribution of cost (i.e., the period of time over which share-based payment awards vest and the pattern of cost recognition over that period). Additionally, the amendments specify that Topic 718 applies to all share-based payment transactions in which a grantor acquires goods or services to be used or consumed in the grantor’s own operations by issuing share-based payment awards, and clarify that Topic 718 does not apply to share-based payments used to effectively provide (1) financing to the issuer, or (2) awards granted in conjunction with selling goods or services to customers as part of a contract accounted for under Topic 606, Revenue from Contracts with Customers. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements.

As of January 1, 2019, the Company adopted ASU No. 2017-08, Receivables - Nonrefundable Fees and Other Costs (Topic 310-20): Premium Amortization on Purchased Callable Debt Securities. The ASU shortens the amortization period for certain callable debt securities held at a premium. The premium on individual callable debt securities shall be amortized to the earliest call date. This guidance does not apply to securities for which prepayments are estimated on a large number of similar loans where prepayments are probable and reasonably estimable. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements.

Recently Issued Not Yet Effective Accounting Pronouncements:

During interim periods, the Company follows the accounting policies set forth in its annual audited financial statements for the year ended December 31, 2018 as filed with the Securities and Exchange Commission. The following is a summary of recent authoritative pronouncements issued since December 31, 2018 but not yet effective that could impact the accounting, reporting, and/or disclosure of financial information by the Company .

Note 1. Presentation of Financial Information, Continued

Recently Not Yet Effective Accounting Pronouncements (continued):

In June 2016, FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU changed the credit loss model on financial instruments measured at amortized cost, available for sale securities and certain purchased financial instruments. Credit losses on financial instruments measured at amortized cost will be determined using a current expected credit loss model which requires the Company to measure all expected credit losses for financial instruments held at the reporting date based on historical experience, current conditions, and reasonable supportable forecasts. This replaces the existing incurred loss model and is applicable to the measurement of credit losses on financial assets measured at amortized cost and applies to some off-balance sheet credit exposures. Purchased financial assets with more-than-insignificant credit deterioration since origination ("PCD assets" which are currently named "PCI Loans") measured at amortized cost will have an allowance for credit losses established at acquisition as part of the purchase price. Subsequent increases or decreases to the allowance for credit losses on PCD assets will be recognized in the income statement. Interest income should be recognized on PCD assets based on the effective interest rate, determined excluding the discount attributed to credit losses at acquisition. Credit losses relating to available-for-sale debt securities will be recognized through an allowance for credit losses. The amount of the credit loss is limited to the amount by which fair value is below amortized cost of the available-for-sale debt security. The amendments in this update are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years for the Company and other SEC filers. Early adoption is permitted and if early adopted, all provisions must be adopted in the same period. The amendments should be applied through a cumulative-effect adjustment to retained earnings as of the beginning of the period adopted. A prospective approach is required for securities with other than temporary impairment recognized prior to adoption. The Company is continuing its implementation efforts through its company-wide implementation team. The implementation team meets periodically to discuss the latest developments and ensure progress is being made. The team also keeps current on evolving interpretations and industry practices related to ASU 2016-13 via webcasts, publications, conferences, and peer bank meetings. The team continues to evaluate and validate data resources and different loss methodologies. The Company’s preliminary evaluation indicates the provisions of ASU No. 2016-13 are expected to impact the Company’s consolidated financial statements, in particular an increase to the level of the reserve for credit losses. However, the Company continues to evaluate the extent of the potential impact. The guidance of ASU 2016-13 was recently amended by ASU 2018-19, Codification Improvements to Topic 326, Financial

Instruments - Credit Losses, which changed the effective date for non-public companies and clarified that operating lease receivables are not within the scope of the standard.

Reclassifications:

Certain captions and amounts in the 2018 consolidated financial statements were reclassified to conform to the 2019 presentation and these reclassifications had no impact on net income or shareholders' equity as previously reported.

Earnings per common share:

Basic earnings per common share represents income available to common shareholders divided by the weighted-average number of common shares outstanding during the period. Diluted earnings per common share reflects additional common shares that would have been outstanding if dilutive potential common shares had been issued, as well as any adjustment to income that would result from the assumed issuance (excluding tax impact). Potential common shares that may be issued by the Company relate solely to outstanding stock options, determined using the treasury stock method, and restricted stock awards, determined by the fair value of the Company's stock on date of grant.