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Long-Term Debt (Narrative) (Details) $ in Thousands |  |  |  | 12 Months Ended |  |
--- | --- | --- | --- | --- | --- | ---
Mar. 21, 2018 USD ($) | Jan. 02, 2018 shares | Feb. 13, 2017 shares | Dec. 31, 2017 USD ($) | Mar. 28, 2018 USD ($) | Dec. 31, 2016 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |
Credit facility amount outstanding |  |  |  | $ 0 |  | $ 2,400
Proceeds from rights offering |  |  |  | $ 2,699 |  |
Subsequent Event [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Credit facility amount outstanding |  |  |  |  | $ 0 |
Prosperity Bank [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Credit facility maturity date |  |  |  | Jul. 31, 2020 |  |
Rate above prime |  |  |  | 0.50% |  |
Credit facility maximum borrowing capacity |  |  |  | $ 50,000 |  |
Credit facility current borrowing capacity |  |  |  | $ 1,250 |  |
Prosperity Bank [Member] | Subsequent Event [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Interest rate | 5.00% |  |  |  |  |
Credit facility current borrowing capacity | $ 2,000 |  |  |  |  |
Maximum [Member] | Prosperity Bank [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Funded debt to EBITDA |  |  |  | 3.5 |  |
Minimum [Member] | Prosperity Bank [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Current ratio |  |  |  | 1 |  |
Interest coverage |  |  |  | 3.0 |  |
Rights [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Common stock, New shares issued | shares |  |  | 4,498,698 |  |  |
Directors, CFO And Interim CEO [Member] | Subsequent Event [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Common stock, New shares issued | shares |  | 4,569 |  |  |  |
Directors, Management, And Affiliates [Member] | Rights [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Common stock, New shares issued | shares |  |  | 3,293,407 |  |  |

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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://www.xbrl.org/2003/role/presentationRef -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://www.xbrl.org/2003/role/presentationRef -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 Reference 3: http://www.xbrl.org/2003/role/presentationRef -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 + Details
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