| Note 14 - Regulatory Matters (Details Textual) $ in Millions | Dec. 31, 2019  USD ($) | 
|---|---|
| Cumulative Dividends | $ 339 | 
| Excess Tier One Common Equity Risk Weighted Assets | 2.50% | 
| X | ||||||||||
| 
- Definition The amount of excess Tier 1 common equity divided by risk-weighted assets which are assets that are weighted for credit risk according to a formula used by the Reserve Bank. No definition available. 
 | 
| X | ||||||||||
| 
- Definition Amount of cumulative cash dividends distributed to shareholders. No definition available. 
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