Note 2 - Securities - Proceeds from Sale of Securities and Related Gross Gains (Details) - USD ($) $ in Thousands  | 
12 Months Ended | |
|---|---|---|
Dec. 31, 2021  | 
Dec. 31, 2020  | 
|
| Sales of securities available for sale | $ 6,769 | $ 12,112 | 
| Gross gain realized on the sale of securities available for sale | 131 | 114 | 
| Gross loss realized on the sale of securities available for sale | $ 0 | $ (55) | 
| X | ||||||||||
- Definition Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
  | 
| X | ||||||||||
- Definition Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  |