Federal Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 19, 2012	Nov. 23, 2010
Income Tax [Line Items]
Net (loss) income	$ (15,800,000)
Federal income tax expense (benefit)	0	0	33,401,000
Income tax rate	35.00%
Income tax paid	0	0	0
Accrued interest					13,000,000
Current tax benefit			13,000,000
Valuation allowance equal to net deferred federal income tax asset	100.00%	100.00%
Abandoned stock				8,370,000,000
Change in equity ownership				50.00%
Available and utilizable NOL	5,970,000,000
NOLs expiration date	2029
Reserve for uncertain federal income tax position	0
Income tax interest income, expense or penalties	$ 0	$ 0	$ 0