Consolidated Statements of Cash Flows - Successor [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 39,619	$ 123,777
Cash flows from operating activities:
Net income attributable to common shareholders	305,704	(125,441)
Net income (loss)	305,704	(125,441)
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	181	270
Amortization of bond premium and discount	(77,427)	(36,178)
Share-based compensation	4,612	1,521
Deferred income taxes	1,145	26
Current income taxes	(8,439)	11,550
Unearned premiums, net	(18,329)	(36,272)
Losses and loss expenses, net	(1,371,840)	131,188
Ceded premiums payable	(1,425)	(2,328)
Investment income due and accrued	(3,926)	(1,250)
Premium receivables	5,601	8,630
Accrued interest payable	(82,992)	4,866
Amortization of insurance intangible assets	28,636	37,525
Net mark-to-market (gains) losses	452	(853)
Net realized investment gains	(4,862)	4,896
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Net of Tax, Portion Attributable to Parent, Available-for-sale Securities	299	3,942
Other-than-temporary impairment charges	299	3,942
(Gain) loss on extinguishment of debt	(3,115)	(2,741)
Variable interest entity activities	(574)	(3,701)
Increase (Decrease) in Derivative Assets and Liabilities	438	(101)
Other, net	34,299	(337)
Net cash used in operating activities	(1,191,562)	(4,788)
Cash flows from investing activities:
Proceeds from sales of bonds	296,078	305,541
Proceeds from matured bonds	103,995	227,741
Purchases of bonds	(77,469)	(439,473)
Proceeds from sales of other invested assets	31,327	121,353
Purchases of other invested assets	(11,758)	(139,561)
Change in short-term investments	236,262	83,550
Change in cash collateral receivable	(979)	9,615
Proceeds From Financial Guaranty Variable Interest Entity Assets	79,917	64,946
Other, net	(377)	(1,189)
Net cash provided by investing activities	656,996	232,523
Cash flows from financing activities:
Proceeds From Issuance of Tier II Notes	240,000	0
Paydowns of a secured borrowing	(8,797)	(10,355)
Payments for Repurchase of Warrants	8,092
Paydown of Financial Guaranty Variable Interest Entity Liabilities	(79,917)	(62,672)
Warrants Purchased During Period Dollars	0
Payments for investment agreement draws	0	(82,358)
Payments for extinguishment of long-term debt	(191,258)	(43,666)
Payments of Debt Issuance Costs	(9,221)	0
Payments Related to Tax Withholding for Share-based Compensation	(1,025)	(1,268)
Net cash used in financing activities	(50,218)	(200,319)
Effect of Exchange Rate on Cash and Cash Equivalents	(278)	463
Net cash flow	(585,062)	27,879
Cash, cash equivalents, and restricted cash at end of period	$ 38,485	$ 118,772