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Note 2 - Summary of Significant Accounting Policies (Details Textual) $ / shares in Units, $ in Thousands |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Feb. 27, 2019 shares | Dec. 31, 2018 USD ($) $ / shares | Sep. 30, 2018 $ / shares | Jun. 30, 2018 $ / shares | Mar. 31, 2018 $ / shares | Dec. 31, 2017 $ / shares | Sep. 30, 2017 $ / shares | Jun. 30, 2017 $ / shares | Mar. 31, 2017 $ / shares | Dec. 31, 2018 USD ($) $ / shares shares | Dec. 31, 2017 USD ($) $ / shares shares
Number of Variable Interest Entity |  |  |  |  |  |  |  |  |  | 1 |
Maximum Maturity Period for Cash Equivalents |  |  |  |  |  |  |  |  |  | 90 days |
Number of Investment Portfolios |  |  |  |  |  |  |  |  |  | 3 |
Number of Securities Held as Trading Securities |  |  |  |  |  |  |  |  |  | 0 | 0
Unrecognized Tax Benefits, Ending Balance | $ |  | $ 0 |  |  |  |  |  |  |  | $ 0 |
Number of Reportable Segments |  |  |  |  |  |  |  |  |  | 2 | 2
Earnings Per Share, Diluted, Total | $ / shares |  | $ 0.22 | $ 0.03 | $ 0.06 | $ 0.06 | $ (0.30) | $ 0.10 | $ 0.06 | $ 0.06 | $ 0.37 | $ (0.07)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross |  |  |  |  |  |  |  |  |  | 62,150 | 70,600
Service and Other Charges On Deposit Accounts, Mortgage Fees from Secondary Market Transactions at the Bank, ATM Fee Income and Other Non-Interest Income [Member] |  |  |  |  |  |  |  |  |  |  |
Revenues, Total | $ |  |  |  |  |  |  |  |  |  | $ 3,200 | $ 3,000
Non Qualified Stock Options [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | 66,150 |  |  |  |  |  |  |  |  |  |
Restricted Stock [Member] | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted | 5,520 |  |  |  |  |  |  |  |  |  |
Previously Reported [Member] |  |  |  |  |  |  |  |  |  |  |
Earnings Per Share, Diluted, Total | $ / shares |  |  |  |  |  |  |  |  |  |  | $ (0.06)
Core Deposits [Member] |  |  |  |  |  |  |  |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  |  |  |  |  |  |  |  |  | 7 years |
Minimum [Member] |  |  |  |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  |  |  |  |  |  |  |  | 3 years |
Maximum [Member] |  |  |  |  |  |  |  |  |  |  |
Property, Plant and Equipment, Useful Life |  |  |  |  |  |  |  |  |  | 40 years |

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