Financial Derivatives (Schedule of Credit Derivatives) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value	$ 150,343	$ 143,996
Derivative Liability	(40,425)	(61,776)
Derivative Assets (Liabilities), at Fair Value, Net	109,918	82,220
Credit default swaps on asset-backed indices
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value	1,948	3,318
Derivative Liability	(32)	(32)
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Long
Credit Derivatives [Line Items]
Notional value	226	230
Financial derivatives–assets, at fair value	$ 12	$ 12
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Long | Weighted Average
Credit Derivatives [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
Credit Derivatives [Line Items]
Notional value	$ 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
Credit Derivatives [Line Items]
Remaining Years to Maturity	34 years 10 months 17 days	35 years 1 month 9 days
Credit default swaps on asset-backed indices | Financial Derivatives - Liabilities | Long
Credit Derivatives [Line Items]
Notional value	$ 60	$ 60
Derivative Liability	$ (32)	$ (32)
Credit default swaps on asset-backed indices | Financial Derivatives - Liabilities | Long | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	24 years 11 months 19 days	25 years 2 months 19 days
Credit default swaps on corporate bond indices
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value	$ 11,830	$ 7,259
Derivative Liability	(22,037)	(15,894)
Credit default swaps on corporate bond indices | Financial Derivatives - Assets | Long
Credit Derivatives [Line Items]
Notional value	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
Credit Derivatives [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
Credit Derivatives [Line Items]
Remaining Years to Maturity	0 days	0 days
Credit default swaps on corporate bond indices | Financial Derivatives - Liabilities | Short
Credit Derivatives [Line Items]
Notional value	$ 674,269	$ 537,299
Remaining Years to Maturity	4 years 10 months 24 days	4 years 10 months 2 days
Derivative Liability	$ (22,037)	$ (15,894)
Credit default swaps on asset-backed securities
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value	8	8
Credit default swaps on asset-backed securities | Financial Derivatives - Assets | Short
Credit Derivatives [Line Items]
Notional value	45	45
Financial derivatives–assets, at fair value	$ 8	$ 8
Credit default swaps on asset-backed securities | Financial Derivatives - Assets | Short | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	11 years 5 months 26 days	11 years 8 months 26 days
Credit default swaps on corporate bonds
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value	$ 107	$ 25
Derivative Liability	(246)	(225)
Credit default swaps on corporate bonds | Financial Derivatives - Assets | Long
Credit Derivatives [Line Items]
Notional value	2,000	2,000
Financial derivatives–assets, at fair value	$ 107	$ 25
Credit default swaps on corporate bonds | Financial Derivatives - Assets | Long | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	1 year 8 months 19 days	1 year 11 months 19 days
Credit default swaps on corporate bonds | Financial Derivatives - Liabilities | Short
Credit Derivatives [Line Items]
Notional value	$ 13,000	$ 13,000
Derivative Liability	$ (246)	$ (225)
Credit default swaps on corporate bonds | Financial Derivatives - Liabilities | Short | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	3 years 2 months 19 days	3 years 5 months 19 days
Credit default swaps
Credit Derivatives [Line Items]
Notional value	$ 443,031	$ 441,155
Derivative Assets (Liabilities), at Fair Value, Net	$ (8,422)	$ (5,541)
Credit default swaps | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	7 years 11 months 23 days	7 years 9 months 21 days
Credit Default Swap, Selling Protection [Member]
Credit Derivatives [Line Items]
Fair Value	$ 11,917	$ 7,264
Notional value	$ 286,286	$ 151,290