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Debt - Ark Stand By Letters of Credit Narrative (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Apr. 07, 2020
--- | --- | ---
Debt Instrument |  |
Total commitment under revolving credit facility |  | $ 291.4
Short-term investments |  |
Debt Instrument |  |
Investments pledged as collateral | $ 50.0 |
Uncollateralized | Letter of Credit | Secured Debt | Ark |  |
Debt Instrument |  |
Total commitment under revolving credit facility | 50.0 |
Collateralized | Letter of Credit | Secured Debt | Ark |  |
Debt Instrument |  |
Total commitment under revolving credit facility | $ 100.0 |

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