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Fair Value of Assets and Liabilities (FY) (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | $ 151,944 | $ 129,422
Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 | 0
Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 151,944 | 129,422
Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 | 0
U.S. Government-sponsored enterprises (GSEs) [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 25,776 | 17,723
U.S. Government-sponsored enterprises (GSEs) [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 | 0
U.S. Government-sponsored enterprises (GSEs) [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 25,776 | 17,723
U.S. Government-sponsored enterprises (GSEs) [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 | 0
Muncipal Securities [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 9,003 | 8,019
Muncipal Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 | 0
Muncipal Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 9,003 | 8,019
Muncipal Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 | 0
Other Debt Securities [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 950 |
Other Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 |
Other Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 950 |
Other Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 |
Mortgage-backed securities [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 116,215 | 103,680
Mortgage-backed securities [Member] | Fair Value, Inputs, Level 1 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 0 | 0
Mortgage-backed securities [Member] | Fair Value, Inputs, Level 2 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | 116,215 | 103,680
Mortgage-backed securities [Member] | Fair Value, Inputs, Level 3 [Member] |  |
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] |  |
Securities available-for-sale | $ 0 | $ 0

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