Income Taxes - Summary of Deferred Taxes (Detail) $ in Thousands	Sep. 30, 2020 USD ($)
Deferred tax assets:
Reserves for expected costs of liquidation and Residual Wind-Down Claims and Costs	$ 1,927
Net operating loss carryovers	53,631
Gross deferred tax assets	55,558
Less: Valuation allowance	(55,541)
Deferred tax asset, net of valuation allowance	17
Deferred tax liabilities:
Accrued investment income	(17)
Gross deferred tax liabilities	(17)
Net deferred taxes	$ 0