Borrowings - Short-Term Borrowings (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Short-Term Debt [Line Items]
Short-Term Debt	$ 58,400,000	$ 426,800,000
Securities Sold under Agreements to Repurchase
Short-Term Debt [Line Items]
Short-Term Debt	$ 28,500,000	$ 253,700,000
Short-term borrowings interest rate	6.35%	4.38%
Other Debt
Short-Term Debt [Line Items]
Short-Term Debt	$ 0	$ 365,700,000
Short-term borrowings interest rate		7.35%
Carrying value of pledged investments		$ 371,000,000