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Capital Stock - ATM Agreements (Details) - 2018 ATM Agreement - USD ($) $ in Millions | Jun. 30, 2021 | Dec. 18, 2018
--- | --- | ---
Sale of stock |  |
Maximum amount of shares to be issued | $ 50.0 | $ 30.0
Maximum |  |
Sale of stock |  |
Sales commission paid per transaction (as a percent) |  | 3.00%
Common Stock |  |
Sale of stock |  |
Shares issued (in shares) | 0 | 0

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