Income Taxes (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2007	Dec. 31, 2013
Tax provision (benefit) [Abstract]
Tax provision (benefit) before valuation allowance	$ 23,120,000	$ (21,590,000)
Change in valuation allowance	(22,394,000)	22,729,000
Provision for (benefit from) income taxes	726,000	1,139,000
Increase (decrease) in deferred tax valuation allowance, included in other comprehensive income	(13,300,000)	3,000,000
Valuation allowance	968,600,000			1,004,200,000
Net operating loss carryforwards, regular tax basis	2,600,000,000
Net operating loss carryforwards for computing the alternative minimum tax	1,700,000,000
Information regarding income tax examinations [Abstract]
Amount of IRS assessment for unpaid taxes and penalties related to REMIC issue			197,500,000
Estimate of federal interest that may be due	151,000,000
Estimate of additional state income taxes and interest that may be due	46,300,000
Amount of payment made related to the IRS assessment on the REMIC issue			65,200,000
Total amount of unrecognized tax benefits	105,600,000
Total amount of the unrecognized tax benefits that would affect our effective tax rate	93,000,000
Unrecognized tax benefits, accrued interest	$ 26,300,000			$ 26,100,000