Derivative Financial Instruments - Gains and Losses Arising from Derivative Instruments (Details) - Derivatives Not Designated as Hedging Instruments - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Interest rate futures
Derivative [Line Items]
Net Realized Gains (Losses) on Derivative Instruments	$ 2,828	$ 17,692	$ 8,599	$ 66,805
Net Change in Unrealized Appreciation (Depreciation) on Derivative Instruments	(364)	6,027	(2,416)	7,349
TBAs
Derivative [Line Items]
Net Realized Gains (Losses) on Derivative Instruments	7,421	(10,147)	4,900	3,032
Net Change in Unrealized Appreciation (Depreciation) on Derivative Instruments	$ 4,927	$ 10,180	$ (5,379)	$ (506)