Income Taxes - Significant Portions of Deferred Tax Liabilities and Deferred Tax Assets (Detail) - Successor [Member] - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deferred tax liabilities:
Insurance intangible	$ 174,938	$ 177,864
Deferred Tax Liabilities, Debentures	53,274	28,387
Variable interest entities	23,221	22,817
Investments	19,003	28,798
Unearned premiums and credit fees	50,569	51,485
Other	11,722	9,402
Deferred Tax Liabilities, Gross, Noncurrent	332,727	318,753
Deferred tax assets:
Net operating loss and capital carryforward	688,693	775,917
Loss reserves	298,888	264,624
Other	1,819	2,140
Sub total deferred tax assets	996,219	1,048,266
Valuation allowance	698,296	763,172
Total deferred tax assets	297,923	285,094
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation	6,819	5,585
Deferred Tax Assets, Net	$ (34,804)	$ (33,659)