XML 164 R146.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Fair Value of Assets and Liabilities (FY) (Details 2) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Jun. 30, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Impaired loans | $ 769,000 | $ 239,000 | $ 407,000
Foreclosed assets | $ 3,254,392 | $ 2,386,239 | $ 3,524,239
Impaired Loans [Member] |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Valuation Technique | Third Party Appraisal | Cash Flow |
Significant Other Unobservable Input | Appraisal Discounts | Discounted Cash Flow / Appraisal Discounts |
Weighted Average of Input (as a percent) | 35.50% | 2.40% |
Foreclosed assets [Member] |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Valuation Technique | Third Party Appraisal | Appraisal |
Significant Other Unobservable Input | Appraisal Discounts | Appraisal Discounts |
Weighted Average of Input (as a percent) | 17.80% | 12.20% |

X
- Definition Weighted average rate of the fair value input. + References No definition available. + Details
Name: | smbk_FairValueInputsWeightedAverageOfInput
Namespace Prefix: | smbk_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of significant assumptions used by management to measure fair value. + References No definition available. + Details
Name: | smbk_FairValueMeasurementsSignificantAssumption
Namespace Prefix: | smbk_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the inputs and valuation technique(s) used to measure fair value. + References No definition available. + Details
Name: | smbk_FairValueMeasurementsValuationTechnique
Namespace Prefix: | smbk_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Representing impaired loans fair value disclosure. + References No definition available. + Details
Name: | smbk_ImpairedLoansFairValueDisclosure
Namespace Prefix: | smbk_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying amount as of the balance sheet date of all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance; includes real and personal property; equity interests in corporations, partnerships, and joint ventures; and beneficial interests in trusts. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5162-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4437-111522 + Details
Name: | us-gaap_ForeclosedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=smbk_ImpairedLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByAssetClassAxis=smbk_ForeclosedAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |