Financial Derivatives (Schedule of Credit Derivatives) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value-	$ 65,082	$ 18,894
Derivative Liability	(16,528)	(12,298)
Derivative Assets (Liabilities), at Fair Value, Net	48,554	6,596
Credit default swaps on asset-backed indices
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value-	1,193	1,751
Derivative Liability	(38)	(39)
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Long
Credit Derivatives [Line Items]
Notional value	467	484
Financial derivatives–assets, at fair value-	$ 6	$ 7
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Long | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	24 years 4 months 17 days	24 years 3 months 25 days
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Short
Credit Derivatives [Line Items]
Notional value	$ 10,471	$ 13,947
Financial derivatives–assets, at fair value-	$ 1,187	$ 1,744
Credit default swaps on asset-backed indices | Financial Derivatives - Assets | Short | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	43 years 4 months 6 days	42 years 5 months 4 days
Credit default swaps on asset-backed indices | Financial Derivatives - Liabilities | Long
Credit Derivatives [Line Items]
Notional value	$ 89	$ 89
Derivative Liability	$ (38)	$ (39)
Credit default swaps on asset-backed indices | Financial Derivatives - Liabilities | Long | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	27 years 1 month 28 days	27 years 4 months 28 days
Credit default swaps on asset-backed indices | Financial Derivatives - Liabilities | Short
Credit Derivatives [Line Items]
Notional value	$ 1	$ 491
Derivative Liability	$ 0	$ 0
Credit default swaps on asset-backed indices | Financial Derivatives - Liabilities | Short | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	27 years 9 months 3 days	24 years 5 months 1 day
Credit default swaps on corporate bond indices
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value-	$ 154	$ 156
Derivative Liability	(3,321)	(1,870)
Credit default swaps on corporate bond indices | Financial Derivatives - Assets | Long
Credit Derivatives [Line Items]
Notional value	2,108	2,168
Financial derivatives–assets, at fair value-	$ 103	$ 156
Credit default swaps on corporate bond indices | 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 bond indices | Financial Derivatives - Assets | Short
Credit Derivatives [Line Items]
Notional value	$ 1,550	$ 0
Financial derivatives–assets, at fair value-	$ 51	$ 0
Remaining Years to Maturity	1 year 8 months 19 days
Credit default swaps on corporate bond indices | Financial Derivatives - Assets | Short | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity		0 days
Credit default swaps on corporate bond indices | Financial Derivatives - Liabilities | Short
Credit Derivatives [Line Items]
Notional value	$ 53,589	$ 21,183
Derivative Liability	$ (3,321)	$ (1,870)
Credit default swaps on corporate bond indices | Financial Derivatives - Liabilities | Short | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	4 years 9 months 25 days	4 years 9 months
Credit default swaps on asset-backed securities
Credit Derivatives [Line Items]
Financial derivatives–assets, at fair value-	$ 304	$ 303
Credit default swaps on asset-backed securities | Financial Derivatives - Assets | Short
Credit Derivatives [Line Items]
Notional value	912	910
Financial derivatives–assets, at fair value-	$ 304	$ 303
Credit default swaps on asset-backed securities | Financial Derivatives - Assets | Short | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	13 years 5 months 15 days	13 years 8 months 15 days
Credit default swaps on corporate bonds
Credit Derivatives [Line Items]
Derivative Liability	$ (84)	$ (99)
Credit default swaps on corporate bonds | Financial Derivatives - Liabilities | Short
Credit Derivatives [Line Items]
Notional value	3,400	3,400
Derivative Liability	$ (84)	$ (99)
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	$ 67,259	$ 37,190
Derivative Assets (Liabilities), at Fair Value, Net	$ (1,792)	$ 202
Credit default swaps | Weighted Average
Credit Derivatives [Line Items]
Remaining Years to Maturity	10 years 8 months 19 days	19 years 1 month 6 days
Credit Default Swap, Selling Protection [Member]
Credit Derivatives [Line Items]
Fair Value	$ 71	$ 124
Notional value	$ 2,664	$ 2,741