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CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Increase (Decrease) in Shareholders' Equity [Roll Forward] |  |  |
Distribution of shares of treasury stock for directors' deferred compensation (in shares) | 6,426 | 2,551 | 36,681
Distribution of shares of treasury stock granted for employee restricted stock awards (in shares) | 14,805 | 13,692 | 14,425
Cash dividends declared (in dollars per share) | $ 1.04 | $ 1.04 | $ 1.04
Distribution of shares of treasury stock for directors' compensation (in shares) | 7,923 | 8,465 | 6,015
Distribution of shares of treasury stock for employee compensation (in shares) | 2,274 | 2,373 | 1,784
Sale of shares of treasury stock (in shares) | 36,104 | 13,270 | 14,081
Purchase of shares of treasury stock (in shares) | 257,018 | 4,148 | 2,736
Restricted stock awards, forfeited (in shares) | 112 |  |

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