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Consolidated Statements of Equity (Parenthetical) - shares | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2018 | Sep. 30, 2017 | Dec. 31, 2017 | Dec. 31, 2016
Balance (in units/ shares) | 108,848,223 | 99,608,170 | 101,292,299 | 98,498,651
Conversion of common units to common shares (in units/shares) | 1,895,627 | 337,000 |  |
Issuance of common units resulting from exercise of share options (in shares or units) |  | 5,000 |  |
Share-based compensation issuance, net of redemptions (in units/shares) | 141,633 | 176,477 |  |
Forward Equity Sale Agreement |  |  |  |
Common shares issued during the period (in shares) | 4,527,000 |  |  |
Common Shares | Common Stock Issued to Public Under At-the-Market Program |  |  |  |
Common shares issued during the period (in shares) | 991,664 | 591,042 |  |
Preferred Shares |  |  |  |
Redemption of preferred shares (in shares/units) |  | 6,900,000 |  |

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