Derivatives - Schedule of Futures and Options (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Derivative assets	$ 54,361,000	$ 7,102,000
Derivative liabilities	0	22,595,000
U.S. Treasury futures
Derivative [Line Items]
Derivative assets		26,600,000
Margin Deposit Assets	118,200,000	101,200,000
Variation Margin Receivable, Derivative	1,300,000	6,600,000
Derivative liabilities	219,900,000
Put options on U.S. Treasury futures
Derivative [Line Items]
Derivative assets	0	$ 5,859,000
Put options on U.S. Treasury futures | Short position
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, at Carrying Value	$ 0