Quarterly Information (unaudited) Quarterly Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Gross Premiums Written	$ 2,000	$ 13,000	$ 21,000	$ 3,000	$ 5,000	$ 23,000	$ 1,000	$ 4,000
Premiums Earned, Net, Financial Guarantee Insurance Contracts	20,000	10,000	8,000	28,000	29,000	26,000	26,000	31,000	$ 66,000	$ 111,000	$ 175,000
Net Investment Income	42,000	45,000	86,000	55,000	37,000	58,000	67,000	110,000	227,000	273,000	361,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	0	0	0	(2,000)	0	(1,000)	0	0	(3,000)	(20,000)
Realized Investment Gains (Losses)	9,000	18,000	36,000	17,000	29,000	30,000	47,000	5,000	81,000	112,000	5,000
Derivative, Gain (Loss) on Derivative, Net	12,000	(10,000)	(35,000)	(16,000)	(45,000)	18,000	9,000	25,000	(50,000)	7,000	76,000
Net realized gains (losses) on extinguishment of debt	0	0	0	0	0	0	0	3,000	0	3,000	5,000
Other income	1,000	141,000	(9,000)	1,000	2,000	1,000	2,000	(1,000)	134,000	5,000	0
Variable Interest Entity, Measure of Activity, Operating Income or Loss	7,000	11,000	3,000	16,000	0	2,000	1,000	1,000	38,000	3,000	20,000
Policyholder Benefits and Claims Incurred, Net, Financial Guarantee	(97,000)	(37,000)	133,000	(12,000)	42,000	(34,000)	(33,000)	(247,000)	(13,000)	224,000	(513,000)
Amortization of insurance intangible assets	15,000	17,000	226,000	36,000	29,000	26,000	23,000	29,000	295,000	107,000	151,000
Other Underwriting Expense	23,000	26,000	29,000	25,000	21,000	28,000	26,000	36,000	103,000	112,000	122,000
Interest Expense, Debt	66,000	67,000	67,000	68,000	66,000	66,000	62,000	48,000	269,000	242,000	120,000
Pre-tax (loss) income from continuing operations	(111,000)	69,000	(100,000)	(41,000)	(22,000)	(20,000)	6,000	308,000	(183,000)	273,000	(284,000)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(110,000)	66,000	(128,000)	(43,000)	(20,000)	(22,000)	4,000	306,000	(216,000)	267,000	(329,000)
Net Income (Loss) Attributable to Parent	$ (110,000)	$ 66,000	$ (128,000)	$ (43,000)	$ (20,000)	$ (104,000)	$ 4,000	$ 306,000	$ (216,000)	$ 186,000	$ (329,000)
Earnings Per Share, Basic	$ (2.40)	$ 1.44	$ (2.79)	$ (0.94)	$ (0.45)	$ (2.27)	$ 0.09	$ 6.72	$ (4.69)	$ 4.07	$ (7.25)
Earnings Per Share, Diluted	$ (2.40)	$ 1.41	$ (2.79)	$ (0.94)	$ (0.45)	$ (2.27)	$ 0.09	$ 6.70	$ (4.69)	$ 3.99	$ (7.25)