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Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares | 12 Months Ended
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Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Common stock dividends per share, declared | $ 1.00 | $ 0.96 | $ 0.85
Series A 3% Preferred Stock [Member] |  |  |
Preferred stock, dividend percentage | 3.00% | 3.00% | 3.00%
Preferred stock dividends per share, declared | $ 3.00 | $ 3.00 | $ 3.00
Series B-1 8.48% Preferred Stock [Member] |  |  |
Preferred stock, dividend percentage | 8.48% | 8.48% | 8.48%
Preferred stock dividends per share, declared | $ 8.48 | $ 8.48 | $ 8.48

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