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Common Stock Common Stock (Equity Issuances) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Class of Stock [Line Items] |  |  |
Proceeds from Issuance of Common Stock | $ 64,573 | $ 1,207 | $ 56,380
Common Stock, Shares Authorized | 200,000,000 | 200,000,000 |
Sales Agency Agreement [Member] |  |  |
Class of Stock [Line Items] |  |  |
Common Stock, Shares Authorized | 4,600,000 |  |
Common Stock Shares Authorized Under Sales Agency Agreements Remaining Shares Authorized To Sell | 3,200,000 |  |
Common Stock [Member] |  |  |
Class of Stock [Line Items] |  |  |
Shares issued through sales agency agreements | 1,409,588 | 0 | 1,070,000
Issuance of common stock through sales agency agreements, net of issuance costs | $ 63,571 | $ 0 | $ 54,721

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