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Stockholders' Equity (At-the-Market) (Details) - At The Market - USD ($) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2021 | Aug. 16, 2019
Class of Stock [Line Items] |  |
At-the-market, maximum potential proceeds |  | $ 400.0
Sales commission of gross sales price |  | 2.00%
Number of shares issued (in shares) | 0 |
Value remaining outstanding for future offerings | $ 390.0 |

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- Details
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