Income Taxes - Components of Net Deferred Tax Asset (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred federal income tax asset:
Net operating loss carryforward	$ 2,102,482	$ 2,098,597	$ 2,087,490
Accruals and reserves	3,481	4,531	16,387
Derivative liabilities	19,117
Losses and loss adjustments expense			143
Restricted stock grants	160
As filed adjustments		214	130
Net unrealized loss on investments	16
Capital loss carryforward	52,490	52,603	52,756
Total deferred federal income tax asset	2,177,746	2,155,945	2,156,906
Deferred federal income tax liabilities:
Net unrealized gain on investments		154	425
Losses and loss adjustments expense	411	102
Total deferred federal income tax liabilities	411	256	425
Less: Valuation allowance	$ 2,177,335	2,155,689	2,156,481
Net deferred federal income tax asset		$ 0	$ 0