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Equity (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2018 | Mar. 31, 2017
Class of Stock [Line Items] |  |
Conversion of common units to common shares (in units/shares) | 53,817 | 185,000
Forward Equity Sale Agreement |  |
Class of Stock [Line Items] |  |
Common shares issued under forward equity sale agreements | $ 19,976 |
Forward Equity Sale Agreement | Common Shares |  |
Class of Stock [Line Items] |  |
Number of shares issued | 677,000 |
Common shares issued under forward equity sale agreements | $ 7 |
Remaining capacity under forward equity sale agreements | 6,800,000 |
Common Stock Issued to Public Under At-the-Market Program |  |
Class of Stock [Line Items] |  |
Common shares issued under forward equity sale agreements |  | $ 18,222
Common Stock Issued to Public Under At-the-Market Program | Common Shares |  |
Class of Stock [Line Items] |  |
Common shares issued under forward equity sale agreements |  | $ 5
At-market stock, offering program established, remaining capacity | $ 70,000 |

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