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Shareholders' Equity (Tables) | 12 Months Ended
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Dec. 31, 2020
Stockholders' Equity Note [Abstract] |
Schedule of common and preferred stock activity | The Common and Preferred Stock Activity table below contains additional information about preferred stock conversions during 2020, 2019 and 2018:
Common and Preferred Stock Activity: | Preferred Stock |  | Common stock
(in shares) | Series A Convertible |  | Treasury |  | Outstanding
Balance as of December 31, 2017 | 74,364 |  |  | 7,186,521 |  |  | 87,544,777 |
Repurchase of common stock | — |  |  | — |  |  | — |
Conversion of convertible preferred stock | (2,397) |  |  | — |  |  | 239,748 |
Issuance for share-based compensation plans | — |  |  | — |  |  | 318,915 |
Balance as of December 31, 2018 | 71,967 |  |  | 7,186,521 |  |  | 88,103,440 |
Repurchase of common stock | — |  |  | — |  |  | — |
Conversion of convertible preferred stock | (4,644) |  |  | — |  |  | 464,431 |
Issuance for share-based compensation plans | — |  |  | — |  |  | 617,790 |
Balance as of December 31, 2019 | 67,323 |  |  | 7,186,521 |  |  | 89,185,661 |
Repurchase of common stock | — |  |  | — |  |  | — |
Conversion of convertible preferred stock | (3,734) |  |  | — |  |  | 373,416 |
Issuance for share-based compensation plans | — |  |  | — |  |  | 496,720 |
Balance as of December 31, 2020 | 63,589 |  |  | 7,186,521 |  |  | 90,055,797 |

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