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Federal Home Loan Bank Advances and Other Borrowings (FY) (Details Textual) - USD ($) | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2017 | Oct. 31, 2017 | Dec. 31, 2016 | Aug. 28, 2015
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Long-term line of credit | $ 10,000,000 |  |  |
Carrying value of securities pledged to Federal Home Loan Bank | $ 16,252,434 |  | $ 14,844,441 |
Interest rate at period end (as a percent) | 4.25% |  |  |
Federal Home Loan Bank borrowings, fair value | $ 0 |  | $ 5,765 |
Federal funds purchased | 33,600,000 |  |  |
Fiscal quarter 2019 [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Amortization | 262,500 |  |  |
Fiscal quarter 2020 [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Amortization | 287,500 |  |  |
Fiscal Quarter 2021 [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Amortization | 312,500 |  |  |
Fiscal Quarter 2022 [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Amortization | $ 337,500 |  |  |
Long-term advance dated January 10, 2007, Fixed Interest at 4.25, with a put option exercisable in January 2008 and then quarterly thereafter, principal due in January 2017 [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Federal Home Loan Bank, advances, interest rate (as a percent) | 4.25% |  | 4.25% |
Federal Home Loan Bank Advances [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Line of credit facility, maximum borrowing capacity | $ 36,224,294 |  |  |
Revolving Credit Facility [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Line of credit facility, maximum borrowing capacity |  | $ 15,000,000 |  | $ 8,000,000
Covenant compliance, ratio of non-performing assets as a percentage total assets, not to be greater than | 3.25% |  |  |
Covenant compliance, Texas ratio, not to be greater than (as a percent) | 35.00% |  |  |
Covenant compliance, liquidity ratio, not to be less than (as a percent) | 9.00% |  |  |
Covenant compliance, liquidity ratio in consecutive quarters, not to be less than (as a percent) | 10.00% |  |  |
Covenant terms, return on average assets, next nine months (as a percent) | 0.45% |  |  |
Covenant terms, return on average assets, thereafter (as a percent) | 0.50% |  |  |
Covenant terms, debt service coverage ratio | 0.0125 |  |  |
Covenant compliance, interest coverage ratio, not to be less than | 2.50 |  |  |
Revolving Credit Facility [Member] | Prime Rate [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Initial line of credit period | 90 days |  |  |
Variable rate, floor (as a percent) | 3.50% |  |  |
Basis spread on variable rate (as a percent) | (0.25%) |  |  |
Subsidiaries [Member] |  |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items] |  |  |  |
Total risk-based capital ratio required to well-capitalized | 10.50% |  |  |
Tier 1 risk-based capital ratio required to be well capitalized | 9.50% |  |  |
Tier 1 leverage ratio required to be well capitalized | 8.00% |  |  |

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- Definition Discloses the single interest rate [if] applicable to the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 + Details
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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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