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Fair Value Disclosures - Assets and Liabilities Measured on Nonrecurring Basis (Q2) (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Impaired loans | $ 407 | $ 769 | $ 239
Foreclosed assets | 3,524 | 3,254 | 2,386
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Impaired loans | 0 | 0 | 0
Foreclosed assets | 0 | 0 | 0
Significant Other Observable Inputs (Level 2) [Member] |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Impaired loans | 0 | 0 | 0
Foreclosed assets | 0 | 0 | 0
Significant Other Unobservable Inputs (Level 3) [Member] |  |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |  |
Impaired loans | 407 | 769 | 239
Foreclosed assets | $ 3,524 | $ 3,254 | $ 2,386

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