Senior Unsecured Notes (Details) $ in Millions	Aug. 19, 2019 USD ($)	Sep. 30, 2021
Debt Instrument [Line Items]
Ratio of Indebtedness to Net Capital		37.2
Senior unsecured notes ("Notes") due August 15, 2029
Debt Instrument [Line Items]
Principal amount	$ 50.0
Interest rate	6.25%
Debt to capital ratio covenant	35.00%

Face (par) amount of debt instrument at time of issuance.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant