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Note 5 - Common Shares and Earnings Per Share - Reconciliation of Company's Common Shares (Details) | 12 Months Ended
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Dec. 31, 2019 shares
Common Shares Outstanding, beginning balance (in shares) | 39,664,884
Dividends Reinvested (in shares) | 29,599
Cash Invested (in shares) | 23,740
Vesting of Restricted Stock Units (in shares) | 29,100
Restricted Stock Issued to Directors (in shares) | 15,700
Directors Deferred Compensation (in shares) | 594
Shares Withheld for Individual Income Tax Requirements (in shares) | (55,224)
Common Shares Outstanding, ending balance (in shares) | 40,157,591
Performance Awards 2016 [Member] |
Executive Stock Performance Awards (2016 awards earned) (in shares) | 102,198
At the Market Offering [Member] |
At-the-Market Offering (in shares) | 347,000

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