Financial Derivatives (Schedule of Financial Derivatives) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	$ 198,023	$ 132,518
Financial derivatives–liabilities, at fair value-	(38,520)	(54,198)
Total	159,503	78,320
TBA Securities, Purchase Contracts [Member]
Derivatives, Fair Value [Line Items]
Financial derivatives–liabilities, at fair value-	(681)	(2,007)
TBA Securities, Sale Contracts [Member]
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	6,826	7,985
Financial derivatives–liabilities, at fair value-	(2)	0
Interest rate swaps | Short
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	176,648	116,768
Financial derivatives–liabilities, at fair value-	(67)	(1,408)
Interest rate swaps | Long
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	640	254
Financial derivatives–liabilities, at fair value-	(28,396)	(48,882)
Credit default swaps on asset-backed securities
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	76	76
Credit default swaps on asset-backed indices
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	3,574	3,366
Financial derivatives–liabilities, at fair value-	(33)	(33)
Credit default swaps on corporate bonds
Derivatives, Fair Value [Line Items]
Financial derivatives–liabilities, at fair value-	(268)	(259)
Credit default swaps on corporate bond indices
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	2,298	83
Financial derivatives–liabilities, at fair value-	(8,891)	(1,513)
Total return swaps
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	16	0
Futures
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	6,165	2,772
Financial derivatives–liabilities, at fair value-	(163)	(96)
Futures | Short
Derivatives, Fair Value [Line Items]
Total	6,002	2,676
Forwards
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	263	77
Financial derivatives–liabilities, at fair value-	19	0
Warrants
Derivatives, Fair Value [Line Items]
Financial derivatives–assets, at fair value-	$ 1,517	$ 1,137