Note 7 - Other Borrowed Money (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Sep. 30, 2018
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Due Date, Earliest		2019
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Due Date, Last		2028
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Collateral Pledged		$ 112,120
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds		242,147
Line of Credit Facility, Current Borrowing Capacity		43,500
Long-term Line of Credit, Total		0
Notes Payable to Banks [Member]
Short-term Debt, Total	$ 5,000
Debt Instrument, Term	1 year
Debt Instrument, Interest Rate, Stated Percentage	4.75%
Federal Reserve Bank Advances [Member]
Short-term Debt, Total		$ 0
Minimum [Member]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Interest Rate at Period End		0.98%
Maximum [Member]
Federal Home Loan Bank, Advances, General Debt Obligations, Disclosures, Interest Rate at Period End		3.51%

Contractual interest rate for funds borrowed, under the debt agreement.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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The earliest year of maturity for the advances from the Federal Home Loan Bank as of the Balance Sheet date.

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The last year of maturity for the advances from the Federal Home Loan Bank as of the Balance Sheet date.

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States the interest rate applicable to Federal Home Loan Bank advances outstanding as of the Balance Sheet date.

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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.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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