Financial Derivatives (Credit Default Swaps) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Financial derivatives–assets, at fair value	$ 150,343	$ 143,996
Financial derivatives–liabilities, at fair value-	(40,425)	(61,776)
Fair Value	(109,918)	(82,220)
Credit default swaps on asset-backed indices
Derivative [Line Items]
Financial derivatives–assets, at fair value	1,948	3,318
Financial derivatives–liabilities, at fair value-	(32)	(32)
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Long
Derivative [Line Items]
Notional Amount	(226)	(230)
Financial derivatives–assets, at fair value	$ 12	$ 12
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Long | Weighted Average
Derivative [Line Items]
Remaining Years to Maturity	13 years 9 months	13 years 11 months 26 days
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Short
Derivative [Line Items]
Notional Amount	$ (42,003)	$ (42,101)
Financial derivatives–assets, at fair value	$ 1,936	$ 3,306
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Short | Weighted Average
Derivative [Line Items]
Remaining Years to Maturity	34 years 10 months 17 days	35 years 1 month 9 days
Credit default swaps on corporate bonds
Derivative [Line Items]
Financial derivatives–assets, at fair value	$ 107	$ 25
Financial derivatives–liabilities, at fair value-	(246)	(225)
Credit default swaps on corporate bonds | Financial Derivatives - Assets | Long
Derivative [Line Items]
Notional Amount	(2,000)	(2,000)
Financial derivatives–assets, at fair value	$ 107	$ 25
Credit default swaps on corporate bonds | Financial Derivatives - Assets | Long | Weighted Average
Derivative [Line Items]
Remaining Years to Maturity	1 year 8 months 19 days	1 year 11 months 19 days
Credit default swaps on corporate bond indices
Derivative [Line Items]
Financial derivatives–assets, at fair value	$ 11,830	$ 7,259
Financial derivatives–liabilities, at fair value-	(22,037)	(15,894)
Credit default swaps on corporate bond indices | Financial Derivatives - Assets | Long
Derivative [Line Items]
Notional Amount	(284,000)	(149,000)
Financial derivatives–assets, at fair value	$ 11,830	$ 7,259
Credit default swaps on corporate bond indices | Financial Derivatives - Assets | Long | Weighted Average
Derivative [Line Items]
Remaining Years to Maturity	4 years 5 months 15 days	4 years 5 months 19 days
Credit default swaps on corporate bond indices | Financial Derivatives - Assets | Short
Derivative [Line Items]
Remaining Years to Maturity	0 days	0 days
Credit default swaps on asset-backed securities
Derivative [Line Items]
Financial derivatives–assets, at fair value	$ 8	$ 8
Credit default swaps on asset-backed securities | Financial Derivatives - Assets | Short
Derivative [Line Items]
Notional Amount	(45)	(45)
Financial derivatives–assets, at fair value	$ 8	$ 8
Credit default swaps on asset-backed securities | Financial Derivatives - Assets | Short | Weighted Average
Derivative [Line Items]
Remaining Years to Maturity	11 years 5 months 26 days	11 years 8 months 26 days
Credit default swaps
Derivative [Line Items]
Notional Amount	$ (443,031)	$ (441,155)
Fair Value	$ 8,422	$ 5,541
Credit default swaps | Weighted Average
Derivative [Line Items]
Remaining Years to Maturity	7 years 11 months 23 days	7 years 9 months 21 days